Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS4364086 A
Publication typeGrant
Application numberUS 06/164,717
Publication dateDec 14, 1982
Filing dateJun 30, 1980
Priority dateJan 27, 1978
Also published asDE2803653A1, DE2803653B2, DE2803653C3, US4352125
Publication number06164717, 164717, US 4364086 A, US 4364086A, US-A-4364086, US4364086 A, US4364086A
InventorsFriedrich Guth
Original AssigneeTexas Instruments Deutschland Gmbh
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Alignment and recognition apparatus
US 4364086 A
Abstract
A matrix array of objects, for example semiconductor bars, is located on a carrier such as an X-Y table and the objects are successively brought into the field of view of a television camera for precise alignment with respect to a reference point. Video signals corresponding to an image of the object and its peripheral area are digitized to produce digitized video signals predominantly of a first level corresponding to surface areas of the object and of a second level corresponding to the peripheral areas. The digitized video signals are analyzed during a plurality of data window sets which are associated with axial directions corresponding to directions of movement of the X-Y table and which correspond to areas of the video image which are in a defined position relative to different edges of the video image of the object when the latter is in an aligned position. The data windows of each set correspond to parallel video image regions having predetermined distances from each other in the associated axial direction of displacement of the carrier. If the object is mis-aligned, digitized video signals of the first level will be present in one or more data windows of at least one data window set. Operating signals are derived for each data window set characterizing the number of data windows present in that set in uninterrupted sequence from the inside to the outside of the video image of the object during which appearance of digitized video signals of the first level has occurred. These output signals provide a measure of magnitude and direction of displacement of the object and may be used in adjusting the position of the carrier to bring the object into alignment with respect to the reference position. Following this alignment step, an analysis may be made, again on the basis of digitized video signals, to confirm the presence of an object, and that the object is complete, in the aligned position. In the event a complete object is determined to be present in the aligned position, further analysis may be made on the basis of digitized video signals to determine whether the object has a surface identification mark indicating that the object is a reject.
Images(19)
Previous page
Next page
Claims(54)
What is claimed is:
1. Apparatus for generating signals for use in aligning with respect to a known reference position an object disposed in the field of view of a television camera on a carrier displaceable in two axial directions, the television camera operable to generate an electrical video signal representative of a video image of a surface of the object and a peripheral area surrounding the object in a line raster frame scan comprising:
digitizing means for receiving said video signals and forming therefrom digital video signals of first and second signal levels which for the video signals originating from the object have predominantly said first signal level and for the video signals originating from the peripheral area have said second signal level;
analyzing means for (a) analyzing said digital video signals during a plurality of data window sets which are associated with said axial directions and which correspond to regions of the video image which are in a defined position relative to different edges of the video image of the object when the latter is aligned with respect to the reference position, the data windows of each data window set corresponding to parallel video image regions having predetermined distances from each other in the associated axial direction of displacement of the carrier, and (b) furnishing operating signals characterizing the number of data windows present in each set in uninterrupted sequence from the inside to the outside of the video image of the object during which appearance of said digitized video signals having said first level has occurred, said operating signals providing a measure of magnitude and direction of displacement of said object for use in adjusting said carrier to bring said object into alignment with respect to said reference position.
2. Apparatus according to claim 1, including display means for receiving said video signals and displaying a video image represented by said video signals.
3. Apparatus according to claim 1 or 2, including means for adjusting the position of said carrier in accordance with said operating signals to bring said object directly into alignment with respect to said reference position.
4. Apparatus according to claim 1 or 2, including means for displacing said carrier by predetermined increments; said predetermined distances between the data window of each data window set bearing a predetermined relation to said predetermined increments; and means for utilizing said operating signals to adjust the position of the carrier in said axial directions by a number of increments corresponding to the number of data windows in said uninterrupted sequence represented by the respective associated operating signals.
5. Apparatus for generating signals for use in aligning with respect to a known reference position an object disposed on an adjustable carrier in the field of view of a television camera, the television camera operable to generate an electrical video signal representative of a video image of a surface of the object and a peripheral area surrounding the object in a line raster frame scan comprising:
digitizing means for receiving said video signals and forming therefrom digital video signals of first and second signal levels which for the video signals originating from the object have predominantly said first signal level and for the video signals originating from the peripheral area have said second signal level;
analyzing means for (a) analyzing said digital video signals during a plurality of data window sets which are associated with each other in pairs and correspond to regions of the video image which are in a defined position relative to opposite edges of the video image of the object when the latter is aligned with the reference position, the data windows of each data window set corresponding to distinct video image regions having a predetermined distances from each other and different distances from the associated edge of the image of the object when the latter is aligned with respect to said reference position; (b) furnishing operating signals characterizing the number of data windows present in each set in uninterrupted sequence from the inside to the outside of the video image of the object in which there appear a predetermined minimum number of digital video signals of said first signal level; said operating signals providing a measure of displacement data for corresponding adjustment of said carrier to bring said object into alignment with respect to said reference position.
6. Apparatus according to claim 5, wherein said carrier is displaceable in two axial directions and said pairs of data window sets are associated respectively with said axial directions, and said video image regions corresponding to the data windows are sets of parallel lines extending parallel to the associated axial direction.
7. Apparatus according to claim 5 or 6, including display means for displaying said video signals.
8. Apparatus according to claim 5 or 6, wherein said analyzer means includes means for generating sets of marker line signals to define said data windows; and means for each marker line signal set for registering a count during each marker line signal of that set in which a digital video signal of said first level occurs.
9. Apparatus according to claim 8, wherein said television camera operates with line interlacing and said generating means generates said marker signals only in a selected frame of each television picture.
10. Apparatus according to claim 5 or 6, including sync separator means for receiving video output signals from said televsion camera and for providing frame synchronizing pulses and line synchronizing pulses, and pulse generator means for synchronization by said line synchronizing pulses to produce during a scanning of each television line a sequence of picture element pulses having a frequency large compared with the line frequency, said picture element pulses having defined time locations with respect to the line synchronizing pulse of that scanned line.
11. Apparatus according to claim 10, including sequencer means for receiving frame synchronizing pulses and for receiving and counting line synchronizing pulses and picture element pulses for comparison with numerical values stored by said sequencer means to characterize the location and extent of said data windows to generate on the basis of said comparison data window definition control signals which in each frame or frame line have time locations and extents determined by said stored numerical values.
12. Apparatus according to claim 5 or 6, including means for adjusting the position of said carrier in accordance with said operating signals to bring said object directly into alignment respect to said reference position.
13. Apparatus for generating signals for use in aligning with respect to a known reference position a rectangular semiconductor bar in the field of view of a television camera on a carrier displaceable in two axial directions, the television camera operable to generate an electrical video signal representative of a video image of a surface of the semiconductor bar and a peripheral area surrounding the semiconductor bar in a line raster frame scan comprising;
digitizing means for receiving said video signals and forming therefrom digital video signals of first and second signal levels which for the video signals originating from a surface of the semiconductor bar have predominantly said first signal level and for the video signals originating form the peripheral area have said second signal level;
analyzing means for (a) analyzing said digital video signals during a plurality of data window sets which are associated with said axial directions in pairs and correspond to regions of the video image which define a rectangular area which is occupied by the video image of the semiconductor bar when the latter is aligned with respect to the reference position, the data windows of each data window set corresponding to distinct parallel video image regions having predetermined distances from each other in the associated direction of displacement of the carrier, and (b) furnishing operating signals for each data window set characterizing the number of data window present in that set in uninterrupted sequence from the inside to the outside of the video image of the object during which which appearance of said digitized video signals having said first level has occured, said operating signals defining the magnitude and direction of misalignment of said semiconductor bar use in adjusting said carrier to bring into alignment with respect to said reference position.
14. Apparatus according to claim 13, wherein said video image regions corresponding to the data window sets define a frame enclosing an area corresponding to the dimensions of the video image of the object.
15. Apparatus according to claims 13 or 14, further including display means for displaying the video image represented by the video signals generated by said television camera.
16. Apparatus according to claim 13 or 14, including display means for receiving said video signals for producing a corresponding display; means for generating marker line signals to define said data windows and to modify said digital video signals to produce display areas which bound areas corresponding to said distinct video image regions.
17. Apparatus according to claim 16, wherein the display areas which bound areas corresponding to said distinct video image regions are display representations of the data windows in each set.
18. Apparatus according to claim 13 or 14, wherein said analyzer means includes means for generating sets of marker line signals to define said data windows; and means for each marker line signal set for registering a count during each marker line signal of that set in which a digital video signal of said first level occurs.
19. Apparatus according to claim 18, including television display means wherein said generator circuit means produce two first sets of marker signals whose marker signals each extend over equal portions of television lines and effect the reproduction of horizontal marker lines on said television display means, and two second sets of marker signals which contain pulses lying in two protions of each television line at intervals and which effect the reproduction of vertical marker lines on said television display means.
20. Apparatus according to claim 18, including a television camera operating with line interlacing and said generating circuits generate marker signals only in a selected frame of each television picture.
21. Apparatus according to claim 13 or 14, including sync separator means for receiving video output signals from said television camera and for providing at two separate outputs frame synchronizing pulses and line synchronizing pulses, and pulse generator means for synchronization by said line synchronizing pulses to produce during a scanning of each television line a sequence of picture element pulses having a frequency large compared with the line frequency, said picture element pulses having defined time locations with respect to the line synchronizing pulse of that scanned line.
22. Apparatus according to claim 21, including sequencer means for receiving frame synchronizing pulses and for receiving and counting line synchronizing pulses and picture element pulses for comparison with numerical values stored by said sequencer means to characterize the location and extend of said data windows to generate on the basis of said comparison control signals which in each frame or frame line have time locations and extents determined by said stored numerical values.
23. Apparatus according to claim 13 or 14, including means for analyzing the digital video signal in the entire scanning raster during a predetermined number of instants and for generating a pulse whenever the analyzed video signal has the first signal level, and means for counting the pulses and furnishing a signal whenever the count does not reach a predetermined value in the course of a complete scanning, indicating the lack of a bar in the video image.
24. Apparatus according to claim 13, including means for analyzing the digital video signal in at least one marker field lying within the area of the aligned bar in a predetermined number of instants and for producing a pulse for each said instant the analyzed video signal has the first signal level, and means for couting the pulses and furnishing a signal whenever the count exceeds a predetermined value in the course of a complete frame scan, indicating the presence or completeness of the bar.
25. Apparatus according to claim 14, including means for analyzing the digital video signal in each of four rectangular marker fields corresponding to the four corners of the area occupied by the video image of the digital bar at a predetermined number of instants and for producing a pulse for each said instant the analyzed video signal has the post signal level during that particular marker field, and means for counting the pulses during each marker field and furnishing a signal whenever the count exceeds a predetermined value in the course of a complete scan of the respective marker fields, to indicate the presence or completeness of the bar.
26. Apparatus for generating signals for use in aligning with respect to a known reference position a rectangular semiconductor bar in the field of view of a television camera on a carrier displaceable in two axial directions, the television camera operable to generate an electrical video signal representative of a video image of a surface of the semiconductor bar and a peripheral area surrounding the object in a line raster frame scan for generating electrical video signals which correspond to an image of the scanned area, comprising;
digitizing means for receiving said video signals and forming therefrom digital video signals of first and second signal levels which for the video signals originating from a surface of the semiconductor bar have predominantly said first signal level and for the video signals originating from the peripheral area have said second signal level;
analyzing means for (a) analyzing said digital video signals during a plurality of data window sets which are associated with said axial direction in pairs and correspond to regions of the video image which define an area corresponding to the dimensions of the video image of the semiconductor bar, which area is occupied by the video image of the semiconductor bar when the latter is aligned with respect to the reference position, the data windows of each data window set corresponding to distinct parallel video image regions having predetermined distances from each other in the associated direction of displacement of the carrier, and (b) furnishing output signals for each data window set characterizing the number of data windows present in that set in uninterrupted sequence from the inside to the outside of the video image of the semiconductor bar during which appearance of said digitized video signals having said first level has occurred;
and means for adjusting the position of said carrier in accordance with said output signals to bring the semiconductor bar into alignment with respect to said reference position.
27. Apparatus for generating signals for use in aligning with respect to a known reference position a rectangular semiconductor bar in the field of view of a television camera on a carrier displaceable in predetermined increments in two axial directions, the television camera operable to generate an electrical video signal representative of a video image of a surface of the semiconductor bar and a peripheral area surrounding the object in a line raster frame scan comprising:
digitizing means for receiving said video signals and forming therefrom digital video signals of first and second signal levels which for the video signals originating from a surface of the semiconductor bar have predominantly said first signals level and for the video signals originating from the peripheral area have said second signal level;
analyzing means for (a) analyzing in a single frame scan said digital video signals during a plurality of data window sets which are associated with said axial directions in pairs and correspond to regions of the video image which define an area corresponding to the dimensions of the video image of the semiconductor bar, which area is occupied by the video image of the semiconductor bar when the latter is aligned with respect to the reference position, the data windows of each data window set corresponding to distinct parallel video image regions having predetermined distances from each other in the associated direction of displacement of the carrier, said predetermined distances bearing a predetermined relation to said predetermined increments, and (b) furnishing output signals for each data window set characterizing the number of data windows present in that set in uninterrupted sequence from the inside to the outside of the video image of the semiconductor bar during which appearance of said digitazed video signals having said first level has occurred, and means for utilizing said operating signals for adjusting the position of the carrier in said axial directions by a number of increments corresponding to the number of data windows in said uninterrupted sequence represented by the respective associated operating signals.
28. Apparatus for aligning with respect to a known reference position an object disposed in the field of view of television camera means on a carrier displaceable in two perpendicular axial directions, said television camera means operable to generate an electrical video signal representative of a video image of a surface of the object and a peripheral area surrounding the object in a line raster frame scan comprising:
digitizing means for receiving said video signals and forming therefrom digital video signals of first and second signal levels which for video signals originating from scanned surface areas of the object have predominantly said first signal; level and for the video signals originating from the scanned peripheral area have said second signal level;
applying means for (a) generating marker signals defining sets of data windows, said sets associated with said axial directions in pairs and which correspond to regions of said video image which define essentially rectangular confining dimensions of a said object to be aligned which are is occupied by the video image of the object when the latter is aligned with respect to the reference position, the data windows of each set corresponding to distinct parallel video image lines having predetermined distances from each other in the associated direction of displacement of the carrier; and (b) analyzing said digital video signals during each of said data windows; and
electrical circuit means for detecting occurrence of digitized video signals having said one level during respective ones of said data windows for furnishing output signals for each data window set characterizing the number of data windows present in that set in uninterrupted sequence from the inside to the outside of said area and during which appearance of said digitized video signals having said first level has occurred, said output signals providing object misalignment data signals for controlling adjustment of said carrier to bring said object into alignment with respect to said reference position.
29. Apparatus according to claim 28, including display means for receiving said video signals for producing a corresponding display; and means for modifying said video signals to produce display areas which bound areas corresponding to said distinct video image regions.
30. Apparatus for aligning with respect to a known reference position an object disposed on a carrier in the field of view of television camera means, said carrier adjustable in two orthoganal axial directions, said television camera means operable to generate an electrical video signal representative of a video image of a surface of said object and a peripheral area surrounding the object in a line raster frame scan at a predetermined line frequency together with frame and line synchronizing pulses comprising;
sync separator means for receiving said video output signals to extract said frame synchronizing pulses and line synchronizing pulses;
pulse generator means synchronized by said line synchronizing pulses for producing during scanning of each said television line a sequence of picture element pulses having a frequency large compared with said line frequency, during each said television line said picture element pulses having correspondingly defined time locations with respect to said line synchronizing pulses;
digitizing means for receiving said video output signals and forming therefrom digital video signal levels which for video output signals originating from surface areas of said object having predominantly a first level and for video output signals originating from said peripheral area have a second level;
sequencer means storing numerical values characterizing the locations and time durations of preselected data windows and operable under supervision of said frame synchronizing pulses to count said line synchronization pulses and said picture element pulses with respect to said stored numerical values for producing control signals during selected lines of said frame, said control signals having time locations and durations determined by said stored numerical values;
generator circuit means operable under control of said control signals to generated marker signal sets defining sets of said data windows, data windows of a first pair of data window sets defined during identical portions of two spaced apart sets of said television lines and corresponding to one of said axial directions, and data windows of a second pair of data window sets defined during spaced apart sets of identical by spaced picture element pulse positions in each line of a predetermined group of television lines and corresponding to the other of said axial directions such that said data window sets define together of an area said television frame scan over which said video output signals correspond to a complete image of the surface of said object when aligned with respect to said reference position;
analyzing means for analyzing said digital video signals during each of said marker signal periods and furnishing digital output signals for each said data window set characterizing the number of data windows present in that set in uninterrupted sequence from the inside to the outside of said frame scan area during which appearance of digitized video signals having said first level has occurred, said output signals providing digital measurement of magnitude and direction of misalignment of said object for use in adjusting said carrier to bring said object into alignment with respect to said reference position.
31. Apparatus according to claim 30, wherein said analyzing means includes misalignment detector means operable under supervision of said control signals, and analyzing circuit means for receiving marker signals of respective marker signals sets to initiate operation of said analyzing circuit means to detect said digital video signals of said first level during periods of respective marker signals.
32. Apparatus according to claim 31, wherein at least one of said analyzing circuit means includes latch means having a latch stage for each marker signal of the associated marker signal set and means for switching the latch stage to a predetermined condition after detection during that marker signal of a preselected minimum number of said digitial video signals having said first level.
33. Apparatus according to claim 32, including interrogating circuit means for interrogating the outputs of the latch stages in a predetermined sequence to detect the existence of said predtermined condition, and for terminating said interrogation upon non-existence of said predetermined condition.
34. Apparatus for aligning with respect to a known reference position an object disposed on a carrier in the field of view of television camera means, said carrier adjustable in two orthoganal axial directions;
said television camera means operable to generate an electrical video signal representative of a video image of a surface of said object and a peripheral area surrounding the object in a line raster frame scan at a predetermined line frequency together with frame and line synchronizing pulses;
sync separator means for receiving said video output signals to extract said frame synchronizing pulses and line synchronizing pulses;
pulse generator means synchronized by said line synchronizing pulses for producing during scanning of each said television line a sequence of picture element pulses having a frequency large compared with said line frequency during each said television line said picture element pulses having correspondingly defined time locations with respect to said line synchronizing pulses;
digitizing means for receiving said video output signals and forming therefrom digital video signal levels which for video output signals originating from surface areas of said object have predominantly a first level and for video output signals originating from said peripheral area have a second level;
sequencer means storing numerical values characterizing the locations and time durations of preselected data windows and operable under supervision of said frame synchronizing pulses to count said line synchronization pulses and said picture element pulses with repsect to said store numerical values for producing control signals during selected lines of said frame, said control signals having time locations and durations determined by said stored numerical values;
generator circuit means operable under control of said control signals to generate marker signal sets defining sets of data windows, data windows of a first pair of data window sets defined during identical portions of upper and lower spaced apart sets of said television lines and corresponding to one of said axial directions, and data windows of a second pair of data window sets defined during first and second laterally spaced apart sets of identical spaced picture element pulse positions in each line of a predetermined group of television lines and corresponding to the other of said axial directions such that said data window sets define an enclosed rectangular area of a said television frame over which said video output signals correspond to a complete image of a said object when aligned with respect to said reference position;
analyzing means for analyzing said digital video signals during the individual marker signal periods of each marker signal set in a predetermined sequence which for one marker signal set of each pair of data window sets is the reverse of the sequence for the other set of each pair such that said analysis proceeds from a marker signal of each set corresponding to an initial data window location adjacent said enclosed rectangular area, said analyzing means furnishing digital output signals for each said data window set characterizing the number of data windows present in that set in uninterrupted sequence from the initial data window during which appearance of a predetermined number of digital video signals of said first level has occurred for use to control adjustment of said carrier means to align said object with respect to said reference portion.
35. Apparatus according to claim 34, including display means for receiving said video signals for producing a corresponding display; and means for modifying said video signals to produce display areas which bound areas corresponding to said distinct video image regions.
36. Apparatus according to claim 35, wherein said analyzing means includes for the earlier occurring of the first pair of data window sets and for each one of the second pair of data window sets:
latch means having for each data window of that set a latch stage and means for switching that latch stage to a predetermined condition after detection during the marker signal of that data window of predetermined number of said digital video signals having said first level.
37. Apparatus according to claim 36, including for each latch means, interrogation circuit means operable following operation of all said marker signal sets to interrogate said latch stages in said predetermined sequence to determine the existence of said predetermined condition.
38. Apparatus according to claim 37, including line address counter means, means for advancing said line address counter means in time with generation of said marker signals defining said first pair of data window sets for generating output signal groups representing a numerical designation of said marker signals, means for applying said output signal groups to address inputs of said latch means and of the interrogation circuit means associated with the first pair of data window sets; picture element address counter means; and means for advancing said picture element address counter means in time with generation of the marker signals defining said second pair of data window sets during each line scan for generating output signal groups representing numerical designations of said marker signals, and means for applying said output signal groups to address inputs of the latch means and of the interrogation means associated with the second pair of data window sets.
39. Apparatus according to claim 34, wherein said analyzing means includes misalignment detector means operable under supervision of said control signals, and analyzing circuit means for receiving marker signals of respective marker signal sets to initiate operation of said analyzing circuit means to detect said digital video signals having said first level during periods of respective marker signals.
40. Apparatus according to claim 39, wherein said misalignment detector means includes for each data window set an individual misalignment counter means for counting the number of market signals during which in said uninterrupted succession a predetermined number of digital video signals appears having said first level.
41. Apparatus according to claim 40, including means for simultaneously clocking the misalignment counter means associated with the first pair of data window sets with marker signals of the later occurring of the first and second data window sets.
42. Apparatus according to claim 41, including means for applying digital video signals directly to the misalignment counter means associated with the later occurring set of the first pair of data window sets.
43. Apparatus according to claim 42, including, for each latch means, interrogations means for detecting and counting latch stages having said predetermined condition, and means for applying output signals of said interrogation means respectively to the misalignment counter means associated with the earlier occurring data window set of the first pair of data window sets and with the data window sets of the second pair of data window sets, and wherein the counts of said misalignment counter means represent said digital output signals for use to control the adjustment of said carrier means.
44. Apparatus according to claim 34, including means for adjusting the position of said carrier in accordance with said digital output signals to bring said object directly into alignment with respect to said reference position.
45. Apparatus for generating signals for use in positioning an adjustable carrier on which an object is disposed in the field of view of television camera means and for recognizing on a background surface of said object having one reflection characteristic the presence of an identification area having a different reflection characteristic; and carrier adjustable in two orthogonal axial directions; said television camera means operable to generate an electrical video signal representative of a video image of said surface of the object and a peripheral area surrounding the object in a line raster frame digitizing means operable:
(a) in a first mode for receiving said video signals and forming therefrom first digital video signals which for the video signals corresponding to surface areas of said object have predominantly one signal level and for video signals corresponding to said peripheral area have a different signal level; and
(b) in a second mode for receiving said video signals and forming therefrom second digital video signals which for video signals representative of said background surface area have predominantly one signal level and for video signals representative of said identification area have predominantly another signal level; and analyzing means;
(1) for operation in conjunction with said first mode of operation of said digitizing means to (a) generate marker signals defining sets of data windows, said sets associated with said axial direction in pairs and which correspond to regions of said video image which are in defined positions relative to opposite edges of the video image of the object when the latter is aligned with respect to the reference position, the data windows of each set corresponding to parallel video image regions having predetermined distances from each other in the associated axial direction of displacement of the carrier; (b) analyzing each digital video signals during each of said data windows for detecting occurrence of digitized video signals having said one level during respective ones of said data windows and furnishing output signals for each data window set characterizing the number of data windows present in that set in uninterrupted sequence from the inside to the outside of said area and during which appearance of said digitized video signals having said first level has occurred, said output signals providing misalignment data for adjustment of said carrier to bring said object into alignment with respect to said reference position;
(2) for operation in conjunction with said second mode of operation of said digitizing means (a) to analyze said second digital video signals at a predetermined number of instants during a predetermined number of scanned lines and for generating in each analysis a pulse when said analyzed video signal has said one signal level; and (b) to count the generated pulses and furnish a signal whenever the count exceeds a predetermined value in the course of a complete frame scan indicating the presence of a said identification area.
46. Apparatus according to claim 45, further including display means for displaying the video image represented by the video signals generated by said television camera.
47. Apparatus according to claim 45, including display means for receiving said video signals for producing a corresponding display; means for modifying said video signals to produce display area which bound areas corresponding to said distinct video image regions.
48. Apparatus according to claim 47, wherein said generator circuit means produce two first sets of marker signals whose marker signals each extend over equal portions of television lines and effect the reproduction of horizontal marker lines on said television display means, and two second sets of marker signals which contain pulses lying two portions of each television line at spaced intervals and which effect the reproduction of vertical marker lines on said television display means.
49. Apparatus according to claim 45, including sync separator means for receiving video output signals from said television camera and for providing frame synchronizing pulses and line synchronizing pulses, and pulse generator means for synchronization by said line synchronizing pulses to produce during a scanning of each television line a sequence of picture element pulses having a frequency large compared with the line frequency, said picture element pulses having defined time locations with respect to the line synchronizing pulse of the scanned line.
50. Apparatus according to claim 49, including sequencer means for receiving frame synchronizing pulses and for receiving and counting line synchronizing pulses and picture element pulses for comparison with numerical values stored by said sequencer means to characterize the location and extent of said data windows to generate on the basis of said comparison control signals which in each frame or frame line have time locations and extents determined by said stored numerical values.
51. Apparatus according to claim 49, including means for analyzing the digital video signal in one or more marker fields lying within the area of the aligned object in a predetermined number of instant and for producing in each case a pulse whenever the analyzed video signal has the first signal level, and by means for counting the pulses and furnishing a signal indicating the presence or completeness of the object whenever the count exceeds a predetermined value in the course of a complete frame scan.
52. Apparatus according to claim 45 or 46, including means for adjusting the position of said carrier in accordance with said operating signals to bring said object directly into alignment with respect to said reference position.
53. Apparatus according to claim 45 or 46, including means for displacing said carrier by predetermined increments; said predetermined distances between the data windows of each data window set bear a predetermined relation to said predetermined increments; and means for utilizing said operating signals to adjust the position of the carrier in said axial directions by a number of increments corresponding to the number of data windows in said uninterrupted sequence represented by the respective associated operating signals.
54. Apparatus according to claim 1 or 5 or 13 or 45, wherein said analyzing means is operable to effect the analysis of said digital video signals during a single frame scan.
Description

This is a continuation of application Ser. No. 948,064, filed Nov. 29, 1978 now abandoned.

The invention relates to an apparatus for aligning with respect to a known reference position an object disposed on an adjustable carrier in the field of view of a television camera, the television camera scanning a surface of the object and a peripheral area surrounding the object in a line raster and generating electrical video signals which correspond to an image of the scanned area.

In many fields of industrial mass production the problem arises of bringing identical objects of small dimensions into a work position to carry out certain operations and these objects must be exactly aligned in said position with respect to a predetermined reference position. This applies for example to the production of semiconductor devices such as transistors or integrated circuits which are made in the form of small rectangular wafers, called "bars" in large quantities and must then be mounted and provided with connections. In the known apparatuses of the type mentioned at the beginning the alignment is effected manually by an operator who observes the video image produced by the television camera on the screen of a monitor and displaces the carrier until the object is correctly aligned with respect to the reference position. This mode of operation involves a great deal of work, is time-consuming and difficult, requiring the constant attention of an operator; it also has error sources which lead to increased rejects.

The problem of the invention is to provide an apparatus of the type mentioned at the beginning which carries out a rapid alignment of the objects completely automatically with constant accuracy.

To solve this problem, the apparatus according to the invention includes a digitizing means which receives the video signals and forms therefrom digital video signals of two signal levels, which for the video signals originating from the object have predominantly a first signal level and for the video signals originating from the peripheral area have the second signal level, analysing means for analysing the digital video signals in a plurality of data window sets which are associated with each other in pairs and which correspond to locations adjacent pairs of opposite edges of the object when the latter is aligned with the reference position, the analysing means responding to the appearance of digital video signals of a predetermined signal level in each data window and furnishing output signals characterizing the respective data windows, and by electrical circuits which on the basis of the output signals of the analysing means control the carrier of the object so that the object is aligned with respect to the reference position.

The analysis of digital video signals carried out in the apparatus according to the invention for rapid and accurate completely automatic alignment of the objects provides some further additional advantageous possibilities. Thus, it is possible to examine the objects to be aligned for presence and completeness.

According to an advantageous further development the apparatus according to the invention includes for this purpose a means which analyses the digital video signal in one or more marker fields lying within the area of the aligned object in a predetermined number of instants and produces a pulse whenever the analysed video signal has the first signal level, and a means which counts the pulses and furnishes a signal indicating the presence or completeness of the object when the count exceeds a predetermined value in the course of a complete scanning.

The emitting of the signal may in particular be utilised to initiate an automatic displacement by which the next object is brought into the alignment position.

When the known apparatus mentioned at the beginning was used in the production of semiconductor devices, the operator frequently had to perform an additional function, i.e. determine the presence of certain characteristics on the bars. For it is usual to check the semiconductor devices after their formation but prior to assembly for usability and to mark all the bars which do not fulfil the requirements for the further processing at a predetermined point with an ink dot whose reflection properties clearly differ from those of the bar surfaces so that it is distinguished in the video image displayed on the screen of the monitor for example as a dark area against the bright background of the bar surface. The operator must exclude the bars marked with such an ink dot from further processing.

With the invention an apparatus is provided which completely automatically recognizes the presence of an ink dot or a similar marker.

According to the invention, an apparatus for recognizing the presence of an identification area having a first reflection characteristic on a background surface of an object having a different second reflection characteristic, comprising a television camera which scans a surface area of the object containing the identification area in a line raster and generates video signals which correspond to an image of the scanned surface area is characterized by a digitizing means which receives the video signals and forms therefrom digital video signals having two signal levels which for the video signals originating from the background area have predominantly a first signal level and for the video signals originating from the identification area have predominantly a second signal level, a means which analyses the digital video signals at a predetermined number of instants during a predetermined number of scanned lines and generates in each case a pulse when the analysed video signal has the second signal level, and a means which counts the pulses and furnishes a signal indicating the presence of the identification area whenever the count exceeds a predetermined value in the course of a complete scanning.

Further features and advantages of the invention will be apparent from the following description of an example of embodiment with the aid of the drawings, wherein:

FIG. 1 is a block diagram of an alignment and recognition apparatus according to the invention,

FIG. 2 shows a carrier with semiconductor bars as example of objects which can be aligned with the apparatus of FIG. 1,

FIG. 3 shows the markers produced on the screen with the apparatus of FIG. 1,

FIG. 4 shows three different examples for the alignment of an object with respect to the markers,

FIGS. 5A and 5B together are time diagrams of signals generated in the apparatus of FIG. 1,

FIG. 6 is a more detailed circuit diagram of some components of the apparatus of FIG. 1,

FIG. 7 is a more detailed circuit diagram of the alignment sequencer,

FIG. 8 is a more detailed circuit diagram of the misalignment detector,

FIG. 9 is a block diagram of the displacement control device and an error detector,

FIG. 10 is a more detailed circuit diagram of the marker generator,

FIG. 11 is a more detailed circuit diagram of the ink dot sequencer and the ink dot detector,

FIG. 12 is a more detailed circuit diagram of the bar sequencer and bar detector,

FIG. 13 is a more detailed circuit diagram of the end of slice detector,

FIG. 14 is the circuit diagram of a practical embodiment of the video digitizer,

FIG. 15 is the circuit diagram of a practical embodiment of the line counter of the alignment sequencer,

FIG. 16 is the circuit diagram of a practical embodiment of various components of the alignment sequencer, the misalignment detector and the marker generator,

FIGS. 17A and 17B are the circuit diagram of a practical embodiment of various further components of the misalignment detector,

FIG. 18 is the circuit diagram of a practical embodiment of various components of the ink dot sequencer and

FIG. 19 is the circuit diagram of a practical embodiment of further components of the ink dot sequencer.

The positioning and alignment apparatus illustrated in FIG. 1 is intended to exactly align an object 1 in a horizontal plane with respect to a fixed reference point which is indicated by a vertical arrow R. For this purpose, the positioning and alignment apparatus comprises an X-Y table 2 on the top of which the object 1 is placed and which is adjustable by two motors 3 and 4 in two directions perpendicular to each other, which are denoted as X-direction and Y-direction. The motors 3 and 4 are preferably electrical stepping motors which on each step effect an exactly defined adjustment of the X-Y table 2 in the associated direction, which is for example 10 μm. The stepping motor 3 is the X motor and the stepping motor 4 is the Y motor.

The object 1 may for example be a workpiece on which during the production certain manipulations must be made for which the exact alignment with the reference point R is necessary. Since generally the mass processing of very small workpieces with identical dimensions is involved, a relatively large number of these workpieces may be placed on the X-Y table 2 simultaneously and then aligned successively with the reference point R.

A preferred field of application of the setting and alignment apparatus is the fabrication of semiconductor devices. In the latter, it is of course usual to produce a great number of devices, such as transistors or integrated circuits, simultaneously on a single semiconductor slice of small thickness and then to separate said slice into individual elements which have the shape of rectangular wafers which are called "bars". A large number of such bars is then arranged for example in the manner illustrated in FIG. 2 on a carrier 50.

FIG. 2 shows the originally circular semiconductor slice 51 on which is formed a large number of identical semiconductor devices 52 with rectangular outline. The semiconductor devices 52 all have the same size and are arranged in regular columns and rows. The semiconductor slice 51 is adhered to a support 54 which is for example a resilient plastic foil whose edge is clamped in a frame 55. The slice 51 is thereafter severed into individual bars 52, for example sawing along the edges of the bars 52, so that between the bars intermediate spaces 53 are formed in which the material of the support 54 is visible.

In FIG. 2 the size of the bars 52 is shown exaggerated relatively to the size of the semiconductor slice 51 and for this reason the number of bars in each row and column is only small. In reality the number of bars formed on a semiconductor slice may be very large and amount to several hundreds. Depending on the type of semiconductor device, the size of the bars may vary greatly, but the length of the edges is generally of the order of magnitude of a few millimeters.

As further apparent from FIG. 2 the bars lying at the edge of the slice, i.e. the last bars in each row and column, are generally incomplete and thus not usable. It may also occur that a bar is incomplete or missing entirely within a row.

FIG. 2 also indicates a further step usual in the manufacture of semiconductor devices. After the formation of the semiconductor devices on the semiconductor slice 51, but prior to separating into the individual bars, the semiconductor devices are checked for usability. All bars which do not have the characteristics necessary for further processing are marked at a predetermined location with an ink dot 56 which is shown for some bars in FIG. 2. The ink dot covers a relatively large portion of the surface of the bar so as to be easily distinguished from other dark surface areas which may be present on a usable bar.

To conduct further manipulations on the bars 52 which require an exact alignment of each bar the carrier 50 is mounted on the X-Y table 2 (FIG. 1) and angularly aligned exactly so that the rows lie in the X-direction and the columns in the Y-direction. The X-Y table 2 is displaced stepwise in the Y-direction in such a manner that the bars of a row are brought successively into coincidence with the reference point R. For this purpose, the X stepping motor 3 is in each case driven for a number of steps which corresponds to a displacement of the X-Y table 2 by the distance JX between the centre points of two bars 52 in the X-direction (FIG. 2). After going through a complete row in this manner, the Y stepping motor 4 is actuated for a number of steps which corresponds to a displacement of the X-Y table 2 in the Y-direction by the amount JY between two bars 52; the next row is then run through in the opposite displacement direction.

However, this stepwise displacement of the X-Y table 2 gives only an approximate setting of the bars 52 to the reference point R; in particular, a displacement error can add up to a considerable amount for a large number of bars. For many manipulations it is however necessary for each individual bar to be aligned very accurately with the reference point R, for example so that its centre point (intersection of the diagonals) is in exact coincidence with the reference point R. This alignment is effected by the apparatus illustrated in FIG. 1 following the stepwise displacement of the X-Y table 2.

For this alignment operation the portion of the surface of the carrier 50 lying above the reference point R is projected by an objective 5 onto the photo cathode of a television camera 6. The magnification of the objective 5 is preferably adjustable to adapt to different bar sizes; for example, the magnifications 20:1, 40:1 and 80:1 may be provided. The magnification is chosen in each case so that apart from the bar to be aligned a considerable surrounding area is projected, containing for example several complete bars.

In addition to the stepwise changing of the magnification, the objective 5 is preferably also designed so that an infinitely variable adjustment of the magnification (zoom effect) is possible in each magnification range.

The television camera 6 may be a standard commercially available power line synchronizing camera operating with line interlacing which produces at its output line 7 the analog video signals representing the imaged area together with the frame and line synchronizing pulses necessary for the reproduction. These normal video signals are transmitted via a line 8 to a video selector and mixer 100 which with corresponding adjustment delivers them via a line 9 to a monitor 10 so that a television picture of the area analysed by the objective 5 is displayed on the screen of the monitor 10.

The output line 7 of the television camera 6 is further connected to the input 201 of the video digitizer 200 which compares the analog video signals with two adjustable threshold values which are adjustable independently of each other with the aid of potentiometers 202, 203. The digitizer 200 produces at its output 204 digital video signals DIGVID A having a high level (white) whenever the analog input signal exceeds the threshold value set at the potentiometer 202 and a low level (black) whenever the analog input signal is below the threshold value. The digitizer 200 has a second output 205 at which it produces another digital video signal DIGVID B which has a high level (white) whenever the analog input signal exceeds the threshold value set at the potentiometer 203 and a low level (black) whenever the analog input signal is below said threshold value. The outputs 204 and 205 of the video digitizer 200 are connected to further inputs of the video selector and mixer 100 which is adjustable by a setting device 101 so that it transmits the digital video signal DIGVID A or the digital video signal DIGVID B selectively to the monitor 10, in each case the normal video signal supplied via the line 8 being simultaneously suppressed. The monitor 10 then displays on its screen a digital video image which consists only of white and black picture elements.

The threshold value for the digital video signal DIGVID A is set by means of the potentiometer 202 so that the video signals originating from the base 54 and thus also from the intermediate spaces 53 all remain below this threshold value whilst the video signals originating from the bars 52 for the major part exceed the threshold value. Thus, in the digital television picture reproduced by means of the signal DIGVID A the bars 52 appear predominantly white whilst the intermediate spaces 53 and the carrier 54 surrounding the slice 51 are displayed completely black.

The threshold value for the digital video signal DIGVID B is set by means of the potentiometer 203 so that the video signals originating from the ink dots 56 remain predominantly below this threshold value whilst the video signals originating from the free areas of the bars 52 for the major part exceed said threshold value. Thus, in the digital video signal reproduced by means of the signal DIGVID B the ink dot 56 is displayed black on a predominantly white background. Since the contrast conditions between the bars 52 and the base 54 on the one hand and between the ink dots 56 and the bars 52 on the other may be different, it is expedient to work with two different threshold values.

The output line 7 of the television camera 6 is further connected to the input 301 of a sync separator 300. The latter separates the frame and line synchronizing pulses from the analog video signals and delivers the frame synchronizing pulses FR and the line synchronizing pulses LN at two separate outputs. The sync separator 300 has a third output at which it furnishes a composite synchronizing signal SYNC which contains both the frame synchronizing pulses and the line synchronizing pulses. This third output is connected to a further input of the video selector and mixer 100 so that the synchronizing signals necessary for the picture display on the monitor 10 are also available when one of the digital video signals DIGVID A or DIGVID B is utilized for the display instead of the normal video signal.

The sync separator 300 has a fourth output at which it furnishes a signal TOP which for the entire duration of a selected frame has a high level and for the duration of the other frame a low level. By means of a setting device 302 either the even or the odd frames may be selected for producing the signal TOP; the particular frame selected is used for the marking and evaluation of the television picture explained in detail hereinafter. At a fifth output a short pulse CLR is delivered which coincides with the leading edge of the signal TOP, i.e. with the start of the selected frame.

The output of the sync separator 300 carrying the line synchronizing signal LN is connected to the control input of a picture element generator 11 which furnishes at its output a sequence of picture element pulses PE which define individual picture elements along each television line. The picture element generator is synchronized by the line synchronizing pulse LN so that the picture element pulses PE during the scanning of each television line occur in exactly defined always identical location with respect to the beginning of the television line and thus define picture elements lying vertically below each other in the various television lines. The recurrence frequency of the picture element pulses PE is approximately 9.3 MHz but can be adjusted by means of a setting device 12 for the purpose of an adjustment which will be explained in detail hereinafter.

The outputs of the sync separator 300 and the output of the picture element generator 11 are connected to corresponding inputs of an alignment sequencer 400. Further inputs 401 of the alignment sequencer 400, for simplicity illustrated as a single line, are connected to an input device 402. On the basis of the input signals fed thereto the alignment sequencer 400 generates at eight outputs signals LNX 1, LNX 2, PEX 1, PEX 2, LNG A, LNG B, PEG A and PEG B which occur at predetermined instants and for a fixed duration in each selected frame and are fed on the one hand to a misalignment detector 450 and on the other to a marker generator 500. On the basis of the signals fed thereto the marker generator 500 generates marker signals MK A, MK B, MK C, MK D, which have two signal levels (black and white). It combines these marker signals with a further marker signal MK E supplied thereto from the output of a circuit 600 and forms therefrom a composite marker signal MK A-E which by means of the video selector and mixer 100 can be superimposed on the video signal displayed on the monitor 10 so that on the reproduced television picture white marker lines or marker areas are produced. A further marker signal MK F which can also be superimposed on the displayed video signal is supplied directly to the video selector and mixer 100 from the output of a circuit 700.

The markers displayed on the television screen by means of the marker signals MK A, MK B, MK C, MK D, MK E, MK F are shown more exactly in FIG. 3. The marker signals MK A produce a set A of eight marker lines A7 to A0, each of which occupies a centre portion of a television line. Two successive marker lines of the set A are separated by an interval which corresponds to a television line of the frame (i.e. three television lines of the complete picture). In the same manner the marker signals MK B produce a set B of eight horizontal marker lines B7 to B0 which are completely identical to the marker lines of set A but lie spaced beneath the set A. The marker signals MK C produce a set C of eight vertical marker lines C7 to C0 which extend in the vertical direction above the interval between the lowermost marker line A0 of the set A and the uppermost marker line B7 of the set B but lie to the left outside the area covered by the horizontal marker lines of the sets A and B. Each marker line C has the width of a picture element defined by a picture element pulse PE and two successive vertical marker lines C have a spacing corresponding to two periods of the picture element pulse PE. In the same manner the marker signals MK D produce a set D of eight vertical marker lines D7 to D0 which are completely identical to the lines of the set C but which are spaced from the latter a horizontal distance corresponding to the length of the marker lines A and B. The four marker line sets A, B, C, D thus form a frame enclosing a rectangular area. The television camera 6 is so aligned that the line direction of the television picuture corresponds to the X-direction of the X-Y table 2. Accordingly the edges of the particular bar 52 to be aligned lie parallel to the horizontal marker lines A, B and the vertical marker lines C, D respectively. The lengths of the marker lines and the distances between the marker line sets are adjusted in a manner explained in detail hereinafter so that the rectangular area enclosed by the marker lines corresponds exactly to the size of the television image of a bar. Furthermore, the marker lines assume on the television screen with respect to the imaginary image of the reference point R a location such that the bar is exactly aligned with the reference point R when its image occupies the area enclosed by the marker lines without contacting the innermost marker lines. For example, the image of the reference point R lies exactly in the centre of the rectangle enclosed by the marker lines.

If however the bar 52 is not correctly aligned with the reference point R its image is displaced with respect to the marker lines A, B, C, D so that it covers one or more of the marker lines of one set or of two sets adjoining each other at right-angles. From the number of marker lines covered from the inside towards the outside the magnitude of the necessary correction is apparent and the direction of the correction to be made can be seen from the group to which the covered marker lines belong. This is detected by the misalignment detector 450 which for this purpose, in addition to the output signals of the alignment sequencer 400, receives the marker signals MK A, MK B, MK C, MK D from the marker generator 500 and the digital video signals DIGVID A.

In FIG. 4 three cases of the location of the image of a bar 52 with respect to the marker lines are illustrated. In the diagram of FIG. 4a the image of the bar 52 lies exactly in the rectangle enclosed by the marker lines without covering any of the marker lines. The marker lines are thus disposed in the intervals 53 between the bars 52 (FIG. 2) in which due to the setting of the threshold value at the potentiometer 202 in the digital video signal DIGVID A no high signal values corresponding to white picture elements are contained.

The misalignment detector 450 contains detector circuits which during the times in which the marker signals MK A, MK B, MK C, MK D are generated in the course of the scanning of a frame analyse the digital video signal DIGVID A and respond whenever a white picture element appears in the picture area corresponding to a marker line. Furthermore, the misalignment detector 450 comprises for each of the marker line sets A, B, C, D a counter whose count indicates the number of the marker lines of the respective set which, counted in uninterrupted sequence from the inside to the outside, contain white picture elements in the signal DIGVID A. The counting is terminated as soon as at least one marker line containing only black picture elements appears in the sequence of marker lines counted from the inside to the outside; if marker lines disposed further outside again contain white picture elements they are ignored in the counting.

When the image of the bar 52 assumes the location illustrated in FIG. 4a all four counters of the misalignment detector 450 associated with the marker line sets A, B, C, D have on completion of the analysis zero counts because all the marker lines (or at least the innermost marker lines) of each set contain no white picture elements because they are not covered by the image of the bar 52. This means that the bar 52 is correctly aligned with the reference point R and no correction is necessary. In the illustration of FIG. 4b it is assumed that the image of the bar 52 is displaced upwardly (in the positive Y-direction) with respect to the correct location in such a manner that the upper edge lies between the third and fourth marker lines of the set A. In this case, after completion of the analysis the counter of the misalignment detector 450 associated with the group A exhibits the count 3 whilst the three other counters have zero counts. This indicates that to align the bar the X-Y table 2 must be displaced in the negative Y-direction by an amount which corresponds on the screen of the monitor 10 to a displacement of the image of the bar 52 by 3 marker line spacings.

Depending on the imaging scale selected, the distance between two marker lines of each set corresponds to an exactly defined mechanical displacement of the X-Y table 2. For example, with a magnification of 20:1 the distance between two marker lines can correspond to a displacement of the X-Y table 2 by 20 μm. Thus, in the previously given numerical example in which each adjustment step of one of the stepping motors 3 and 4 corresponds to a displacement of the X-Y table 2 by 10 μm for the case of FIG. 4b the Y motor 4 would have to execute six steps in the direction of rotation corresponding to the negative Y-direction in order to align the bar 52 correctly with the reference point R. The exact calibration may be effected in the Y-direction by fine adjustment of the optical magnification by means of the zoom effect of objective 5 and in the X-direction by changing the frequency of the picture element generator 11 by means of the setting device 12, since this frequency determines the period of the picture element pulses PE and thus the interval of the picture elements along the lines.

FIG. 4c shows the case where the image of the bar 52 covers seven marker lines of the set B and seven marker lines of the set D. In this case, at the end of the analysis the counters of the misalignment detector 450 associated with the sets B and D each have the count seven whilst the counters associated with the sets A and C have zero count. This indicates that a displacement of the X-Y table 2 is necessary by 140 μm in the negative X-direction and by 140 μm in the positive Y-direction and that accordingly each of the two stepping motors 3 and 4 must execute fourteen steps in the corresponding direction of rotation.

The illustration of FIG. 4c shows the maximum alignment correction which can still be carried out with the apparatus described. If the image of the bar 52 is displaced still further so that all the eight marker lines of at least one set are covered an alignment is no longer possible; in this case the associated counter emits an overflow signal.

The misalignment detector 450 has four groups of outputs 451A, 451B, 451C and 451D associated with the four previously mentioned counters. Each output group transmits a three-bit binary number which indicates the count of the respective counter as well as an overflow bit and a direction bit. The overflow bit indicates the previously mentioned overflow state in which a correction in the respective direction is no longer possible and the direction bit indicates the direction (±X, ±Y) in which alignment correction is required. In the case of FIG. 4b the output ground 451A would thus furnish the binary number 010 (3) and a direction bit which indicates that a displacement of the X-Y table 2 in the negative Y-direction is necessary. In the case of FIG. 4c the two output groups 451B and 451D would each furnish the binary number 111 (7) and a direction bit; the direction bit of the output group 451B indicates that a displacement is necessary in the positive Y-direction and the direction bit of the output group 451D indicates that a displacement is necessary in the negative X-direction.

The output groups 451A to 451D are connected to corresponding inputs of a displacement control device 14 which decodes the input signals fed thereto and produces therefrom control signals which are fed via a line 15 to the X motor 3 or via a line 16 to the Y motor 4 and effect rotation of said motors by the necessary number of steps in the respective direction. The displacement control device 14 controls the stepping motors 3 and 4 for executing the adjustments JX and JY as well, the magnitude of which is adjustable by means of a setting device 17 for adaptation to the particular bar processed.

The size and location of the marker lines must of course also be adapted to the particular shape and size of the bars (or other workpieces) to be aligned. This is done by means of digital data supplied from the the control means 402 to the input 401 of the alignment sequencer 400. The control means 402 may be a manually actuated keyboard or a source of stored or programmed information. The digital data fed to the input 401 determine the picture lines or picture elements of the television picture which are used to generate the marker lines.

The part of the system of FIG. 1 so far described effects alignment of the bar or of any other object disposed on the X-Y table 2 with respect to the reference point R.

In the production state illustrated in FIG. 2 of semi-conductor devices the next manipulation to be carried out with the bars 52 is usually the lifting of all usable bars from the base 54, transferring them to a lead frame and mounting them thereon. This manipulation is for example carried out with the aid of a suction head which is reciprocable between two working stations and comprises a controllable suction nozzle which at one working station picks up one bar and releases said bar at the other working station. The bars are brought in succession to the first working station and the lead frames in succession to the second working station. In this case, alignment of the bar with respect to the reference point R is necessary to ensure that each bar assumes an exactly defined location on its lead frame after the transfer.

It is also required that unusable bars, i.e. in particular incomplete bars disposed at the edge and bars marked with an ink dot, are recognized and not transferred so that they remain on the base 54.

Furthermore, the system should automatically detect the complete passage through a row so that by displacement in the Y-direction by an amount JY the next row can be started on. Finally, it must also be recognized when the end of the slice 51 is reached, i.e. no more bars are present, to enable the processed carrier 50 to be replaced by a new carrier.

These functions are performed by the further circuits illustrated in FIG. 1.

The detection of the presence of an ink dot 56 on the bar disposed in the aligned position is done by means of an ink dot sequencer 600 and an ink dot detector 650. The ink dot sequencer 600 produces the already mentioned marker signal MK E which in the marker generator 500 is added to the marker signals MK A to MK D generated therein so that it is displayed on the screen of the monitor 10 together with said marker signals when the video selector and mixer is correspondingly set.

The marker signal MK E has two signal values (white and black) and produces on the screen of the monitor 10 a rectangular field E which lies within the rectangle enclosed by the marker lines A, B, C, D (FIG. 3). For this purpose, the marker signals MK E in a predetermined number of successive television lines occupy in each case the high signal value (white) for the same predetermined number of successive picture elements. The location of the field E is set so that it covers the area in which an ink dot must lie if it is present on the bar. The size of the field E is set so that a considerable portion of its area is occupied by any ink dot present. The size and location of the field E are determined by digital data supplied to the input 601 of the ink dot sequencer 600 by a control means 602.

The marker signals MK E are also fed to the ink dot detector 650 which at a second input receives the digital video signals DIGVID B. It contains a counter which is controlled by the marker signal MK E so that it counts all the black picture elements which are present in the area of the digital image of the bar covered by the field E. When the count exceeds a predetermined threshold number the ink dot detector 650 furnishes at its output a signal DOT which indicates the presence of an ink dot. The threshold number can be adjusted with the aid of a setting device 651 for adaptation to the sizes occurring of the ink dot. The signal DOT appearing at the output of the ink dot detector 650 is fed also to the displacement control device 14 which when this signal appears controls the X motor 3 so that it displaces the X-Y table 2 by the amount JX (FIG. 2) in the X-direction and thus brings the next bar beneath the television camera 6 for alignment; simultaneously, the displacement control device 14 blocks the manipulation to be carried out on the bar, i.e. in the aforementioned example the removal of the bar by means of the suction head. If, on the contrary, the ink dot detector 650 does not furnish an output signal DOT the necessary operation is carried out on the aligned bar and after completion of said operation a flag signal is supplied to the displacement control device 14 and effects displacement of the X-Y table 2 by the amount JX in the X-direction so that the next bar is brought into the alignment position. These operations are repeated for as long as bars are present in the respective row on the carrier 50 (FIG. 2).

A bar sequencer 700 and a bar detector 750 determine whether a bar is incomplete or missing entirely. This can sometimes occur within a row but applies regularly to the end of the row at the edge of the slice 51 (FIG. 2). On reaching the end of the row in most cases an incomplete bar is first detected and on further displacement in the X-direction by the amount JX a missing bar. This fact may be utilized to initiate a displacement in the Y-direction by the amount JY and thereafter a displacement in the opposite X-direction until a complete bar is found in the next row.

FIG. 1 indicates that the line synchronizing pulses LN and the picture element pulses PE are also fed to the ink dot sequencer 600 and the bar sequencer 700 in which they are counted for formation of the marker signals MK E and MK F respectively. The same pulses, as also output signals of the alignment sequencer, are also transmitted to other circuits although in FIG. 1 the corresponding connections have been omitted for clarity.

For this purpose the bar sequencer 700 generates the marker signal MK F which is supplied via the video selector and mixer 100 to the monitor 10 and, if the latter is suitably set, effects the display of one or more marker areas within the rectangle enclosed by the marker lines A, B, C, D. The same marker signal MK F is additionally supplied to an input of the bar detector 750 which receives at a second input the digital video signal DIGVID A. The bar detector 750 contains a counter which is controlled by the marker signal MK F so that it counts all the white picture elements which are present in the portions of the digital video image which are covered by the marker areas produced by means of the marker signal MK F. In the simplest case this marker area may be a rectangle occupying almost the entire area of the bar to be aligned; in this case the bar detector 750 would count all the white picture elements of the digital video image of the bar appearing in said area. In a preferred embodiment illustrated in FIG. 3, however, the marker signals MK F produce four small rectangular or square marker fields F1, F2, F3, F4 which lie in the four corners of the area occupied by the image of the correctly aligned bar. In this case the bar detector 750 counts the white picture elements in all four rectangles. In each case the bar detector 750 furnishes at its output a signal BAR whenever the count exceeds a minimum value set with the aid of a setting device 751. If however the count does not reach this fixedly set minimum value then at least one of the four corners of the bar is not present, i.e. the bar is at least incomplete or is missing entirely. The bar detector 750 then does not furnish a signal BAR at the end of the complete frame, which indicates that the bar is missing or incomplete. The signal BAR is fed to the displacement control device 14; when this signal is lacking the X motor 3 is controlled so that it displaces the X-Y table 2 by the amount JX (FIG. 2) in the X-direction to bring the next bar into the alignment position beneath the television camera 6. If even then no signal BAR appears this can be taken as a criterion showing that the end of the row has been reached; the Y motor 4 is then controlled so that it displaces the X-Y table 2 by the amount JY in a predetermined Y-direction (positive or negative) and the displacement direction of the X motor 3 is reversed.

The end of the slice 51 is detected by an end of slice detector 800 which receives at its input the digital video signal DIGVID A and counts all the white picture elements which appear in the entire television picture. If the count remains under a predetermined fixed threshold number, which may be set by means of a setting device 801, this means that the television picture is substantially occupied by the dark background of the base 54, i.e. the end of the slice 51 has been reached. In this case the end of slice detector 800 furnishes at its output a signal EOS which is also supplied to the displacement control device 14. On the basis of this signal the machine is for example stopped and an alarm triggered for the operator so that he can replace the used carrier 50 by a new one.

The more exact makeup of the various circuits contained in the system of FIG. 1 is illustrated in FIGS. 6 to 13. The function of these circuits and the generation of the various signals will be explained in particular with reference to FIGS. 3 and 5.

As already mentioned, the line direction (horizontal sweep direction) of the television picture corresponds to the X-direction and the direction perpendicular thereto (vertical sweep direction) corresponds to the Y-direction. Each point of the television picture can thus be clearly determined by an X coordinate and a Y coordinate. This makes it possible in particular to clearly define the borders of the various marker lines and marker areas on the screen.

In FIG. 3 at the upper edge in the horizontal direction (X-direction) ten X coordinates X1 to X10 are shown.

At the left edge in the vertical direction (Y-direction) ten Y coordinates Y1 to Y10 are shown.

The coordinate X1 indicates the distance of the first marker line C7 of the set 7 from the left image edge (line begin). The coordinate X2 defines the location of the last marker line C0 of this set and the start of all the horizontal marker lines of the two sets A and B. The coordinate X3 corresponds to the left edge of the two marker fields F1 and F3 whose right edge is defined by the coordinate X4. The two coordinates X5 and X6 correspond to the left and right edge respectively of the marker field E. The coordinates X7 and X8 indicate the location of the left and right edge respectively of the two marker fields F2 and F4. The coordinate X9 corresponds to the end of the horizontal marker lines A and B and the location of the first vertical marker line D7 of the set D and finally a coordinate X10 indicates the location of the last marker line D0 of the set D.

In the same manner the coordinate Y corresponds to the distance of the first horizontal marker line A7 from the upper image edge (start of the frame) and the coordinate Y2 corresponds to the location of the last marker line A0 of the set A and the upper end of the vertical marker lines of the two sets C and D. The coordinates Y3 and Y4 indicate respectively the upper and lower edges of the two marker fields F1 and F2, the coordinates Y5 and Y6 respectively the upper and lower edges of the marker field E and the coordinates Y7 and Y8 the upper and lower edges respectively of the two marker fields F3 and F4. The coordinate Y9 corresponds to the lower end of the vertical marker lines C and D and the horizontal marker line B7, and finally the coordinate Y10 denotes the location of the last horizontal marker line B0.

The coordinates X and Y not only denote spatial points on the television picture but also predetermined instants during the scanning of the television picture. Thus, each coordinate Y can be clearly defined by a predetermined number of line synchronizing pulses LN which are counted from the start of the frame (frame synchronizing pulse FR) or from a preceding Y coordinate. Likewise, each X coordinate can be defined by a predetermined number of picture element pulses PE which are counted from the start of the respective television line (line synchronizing pulse LN) or from a preceding X coordinate. By counting the line synchronizing pulses LN and the picture element pulses PE it is thus possible to define exactly each point within the television picture.

The circuits described hereinafter produce in particular predetermined control signals at instants which correspond to predetermined previously defined X coordinates and Y coordinates and they employ these control signals to generate the marker signals.

In FIGS. 5A and 5B, which are to be placed together along the vertical edge, the marker signals MK A, MK B, MK D, MK E and MK F are illustrated in a row of horizontal time axes within the thickly drawn border and each correspond to a television line of the frame used for the marking. At the upper edge various control signals are illustrated which are produced during the scanning of all or some of the television lines and thus substantially recur with the line frequency. Along the vertical left edge control signals are shown which are generated during the scanning of the frame and thus recur with the frame frequency.

FIG. 6 again shows the components 6, 10, 11, 100, 200, 300 of the system of FIG. 1 and in particular clearly indicates the makeup and function of the video selector and mixer 100. The latter comprises a video amplifier and mixer 102 and a video selector 104. The normal video signal supplied via the line 8 is fed to an input 103 of the video amplifier and mixer 102 and transmitted by the latter after amplification via the line 9 to the monitor 10 unless a digital video signal is requested at the video selector 104. The digital video signals DIGVID A and DIGVID B are supplied to the inputs 105 and 106 respectively of the video selector 104 which also receives at an input 107 the composite marker signal MK A-E and at an input 108 the marker signal MK F. The video selector 104 further comprises four control inputs 109, 110, 111, 112 which are connected to the setting device 101. The video selector 104 is connected via three output lines 113, 114, 115 to the video amplifier and mixer 102 which also receives at an input 116 the composite synchronizing signal SYNC from the sync separator 300.

If instead of the normal video signal the digital video signal DIGVID A is to be displayed on the monitor 10, by means of the setting device 101 a control signal SDIGVID A is applied to the control input 109. The video selector 104 then transmits the digital video signal DIGVID A from the input 105 via the output line 113 to the video amplifier and mixer 102 and simultaneously furnishes on the output line 114 a blanking signal BLK which in the video amplifier and mixer 102 blocks the normal video signal supplied to the input 103. In the same manner the digital video signal DIGVID B is displayed on the monitor 10 when a corresponding control signal SDIGVID B is applied by the setting device 101 to the control input 110. The synchronizing signals necessary for displaying the digital video images are available simultaneously at the input 116 of the video amplifier and mixer 102.

By applying a control signal SMK A-E to the control input 111 of the video selector 104 the composite marker signal MK A-E supplied to the input 107 is transmitted via the output line 115 to the video amplifier and mixer 102 and in the latter superimposed on the particular video signal displayed, i.e. either the normal video signal supplied to the input 103 or the digital video signal DIGVID A or DIGVID B transmitted via the line 113. The marker lines A, B, C, D and the marker field E are then displayed on the screen of the monitor 10 superimposed on the displayed video image. By applying a control signal SMK F to the control input 112 said marker signals may also be added to the marker signal MK F supplied to the input 108 so that the four marker fields F1, F2, F3, F4 are also displayed on the screen of the monitor.

The setting device 101 may for example be part of a manually actuated keyboard which on actuation of corresponding keys emits the necessary control signals in the form of signal levels.

The video digitizer 200 includes a pair of threshold comparators 205 and 206 in the form of operational amplifiers which each receive at their non-inverting input the normal video signal furnished by the television camera 6, whilst the inverting input of the threshold comparator 206 is connected to the tap of the potentiometer 202 and the inverting input of the threshold comparator 207 to the tap of the potentiometer 203. In accordance with the usual mode of operation of such threshold comparators each of them furnishes an output signal of low level (black) as long as the analog signal supplied to the non-inverting input remains below the potential across the inverting input, whereas in the opposite case an output signal with high level (white) is furnished. As already mentioned, the potentiometer 202 is set so that the threshold value for the comparator 206 is adapted to the contrast between the highly reflecting surface of the bar 52 and the weakly reflecting surface of the base 54 or the intervals 53 between the bars whilst the threshold for the comparator 207 is adapted by adjustment of the potentiometer 203 to the contrast between the highly reflecting surface of the bars 52 and the weakly reflecting ink dots 56. The threshold values may be optimally adjusted for the respective particular use by means of the potentiometers 202 and 203.

FIG. 7 shows in greater detail the block circuit diagram of the alignment sequencer 400 which is followed to the right by the misalignment detector 450 illustrated in FIG. 8, this being followed in turn by the displacement control device 14 represented in FIG. 9. The mode of operation of these circuits will be explained in particular with reference to FIGS. 5A and 5B.

As apparent from FIGS. 5A and 5B the first marker signal MK A7 used for the display of the marker line A7 is generated when during the frame scanning the line denoted by the coordinate Y1 is reached. During the scanning of this line the marker signal MK A7 assumes at the instant corresponding to the coordinate X2 a high level which it retains until the instant X9. The same process repeats itself for the other marker signals MK A6 to MK A0 in every other frame line until the coordinate Y2 is reached, no marker signal MK A being generated in the lines in between.

In the frame line following the coordinate Y2 generation of the marker signals MK C and MK D starts for the display of the vertical marker lines C and D. Since these marker lines are perpendicular to the television line direction, only one picture element of them can be displayed in each line. The marker signals MK C and MK D thus consist in each frame line of eight successive short pulses with half the frequency of the picture element pulses PE, the eight pulses of the marker signals MK C being generated between the instants X1 and X2 and the eight pulses of the marker signals MK D between the instants X9 and X10. These pulses recur in each frame line until the frame line corresponding to the coordinate Y9 is reached. Between the coordinates Y9 and Y10 in every other frame line the marker signals MK B are then again generated in the same manner as the marker signals MK A.

In each of the television lines lying between the coordinates Y5 and Y6 the marker signal MK E is also generated and assumes a high level from the instant X5 to the instant X6.

When the markers F1, F2, F3, F4 are displayed as well, the marker signal is additionally generated in the television lines between the coordinates Y3 and Y4 and in the television lines between the coordinates Y7 and Y8 and said signal MK F assumes in each television line a high level from the instant X3 to the instant X4 and from the instant X7 to the instant X8.

The marker signals MK A, MK B, MK C and MK D are produced in dependence upon data which define the coordinates X1, X9, Y1 and Y9 and are recorded in a memory 403 (FIG. 7) which has a capacity of four words× eight bits. These data determine the dimensions and location of the rectangle defined by the marker lines and are fed into the input 401 of the memory with the aid of the control means 402 for adaptation to the particular bar to be aligned. The memory word defining the coordinate X1 is the number of the picture element pulses furnished from the start of the line (line synchronizing pulse LN) up to the coordinate X1; the memory word determining the coordinate X2 is the number of the picture element pulses PE emitted between the instants X1 and X2. The memory word determining the coordinate Y1 is the number of line synchronizing pulses LN emitted from the frame start (frame synchronizing pulse FR) up to the instant Y1; the memory word determining the coordinate Y9 is the number of line synchronizing pulses LN emitted between the instants Y1 and Y2.

The memory 403 has an output 404, an address input 405 and an enable input 406. The output 404, which is in fact a multiple output at which the eight bits of a stored word are emitted in parallel, is connected to the preset inputs 409, 410 of two presettable reverse counters 407, 408. The counter 407 receives at its clock input 411 the line synchronizing pulses LN and serves as line counter. The counter 408 receives at its clock input 412 the picture element pulses PE and serves as picture element counter. The line counter 407 also has a preset control input 413 and two outputs 414, 415; the picture element counter 408 has a preset control input 416 and two outputs 417, 418.

The address input 405 and the enable input 406 of the memory 403 are connected to two outputs of a memory address and strobe decode 419 which at a trigger input 420 receives the frame synchronizing pulses FR and at a further trigger input 421 the line synchronizing pulses LN. A further trigger input 422 is connected to the output 414 of the line counter 407 and a fourth trigger input 423 is connected to the output 417 of the picture element counter 408. The memory address and strobe decode 419 has two further outputs 424 and 425 which are connected to the preset control input 413 of the line counter 407 and to the preset control input 416 of the picture element counter 408 respectively.

The outputs 414 and 415 of the line counter 407 are connected to two inputs of an A/B latch 426 which has two complementary outputs 427, 428, and the outputs 417, 418 of the picture element counter 408 are connected to two inputs of a C/D latch 429 which has two complementary outputs 430, 431.

With each frame synchronizing pulse FR supplied to the input 420 of the memory address and strobe decode 419 the memory is addressed and driven so it furnishes at its output 404 the first memory word which in the previously outlined manner indicates the coordinate Y1 in the form of a redetermined line number. An enable pulse emitted simultaneously at the output 424 of the memory address and strobe decode 419 and supplied to the preset control input 413 of the line counter 407 effects that said counter is preset to the number provided by the memory. The leading edge of the frame synchronizing pulse FR effects the addressing of the memory 403 whilst its trailing edge initiates the transfer of the memory word read to the counter. The same also applies to the other trigger pulses supplied to the inputs 421, 422, 423 of the memory address and strobe decode 419.

The line counter 407 is advanced by the line pulses LN supplied to its clock input 411 so that its content is reduced by one unit for each line pulse. As soon as it has reached zero count it emits at its output 414 a pulse LNX 1. This pulse therefore coincides with the start of the line denoted by the coordinate Y1 (FIG. 5). The pulse LNX 1 is also supplied to the trigger input 422 of the memory address and strobe decode 419 and in the manner outlined above results in the addressing and emission of the memory word from the memory 403 which represents the coordinate Y2 by the number of lines lying between the coordinates Y1 and Y2. The line counter 407 is preset to this number and again counted down by the line synchronizing pulses LN supplied to its clock input 411. When it has reached zero count it emits at its output 415 a pulse LNX 2 which thus coincides with the start of the line corresponding to the coordinate Y2 (FIG. 5). This operation is repeated in each frame so that during the scanning of each frame a pulse LNX 1 and a pulse LNX 2 appears.

The memory is addressed and interrogated by the first line synchronizing pulses LN appearing after the frame synchronizing pulse FR in such a manner that said memory transmits to the picture element counter 408 a memory word which in the previously explained manner represents the coordinate X1 by a number of picture elements. The picture element counter 408 is counted down by the picture element pulses PE supplied to its clock input 412 and on reaching zero count furnishes at its output 417 a pulse PEX 1 which thus occurs during the scanning of a line at the instant corresponding to the coordinate X1 (FIG. 5). The pulse PEX 1 is also applied to the trigger input 423 of the memory address and strobe decode 419 and as a result the memory 403 transfers to the picture element counter 408 the memory word which defines the coordinate X9 by the number of picture elements lying between X1 and X9. The picture element counter is again counted down by the picture element pulses PE and on reaching zero count furnishes at the output 418 a pulse PEX 2 which during the line scanning occurs at the instant corresponding to the coordinate X9. The same operation is initiated by each following line pulse LN so that in each line of the frame a pulse PEX 1 and a pulse PEX 2 are generated.

The pulse LNX 1 applied from the output 414 of the line counter 407 to the A/B latch 426 brings the latter into a position in which the potential at the output 427 assumes a high level and simultaneously the potential at the complementary output 428 assumes a low level. The pulse LNX 2 furnished at the output 415 of the line counter 407 brings the A/B latch 426 into the other position in which the potential at the output 427 is low and the potential at the output 428 is high. The A/B latch 426 thus furnishes at the output 427 a signal LNG A which in each frame has a high level between the coordinates Y1 and Y9 and a low level in the other part of the frame. Correspondingly, the signal LNG B complementary thereto at the output 428 has from the coordinate Y9 of a frame to the coordinate Y1 of the next frame a high level but a low level between the coordinates Y1 and Y9 of each frame.

In the same manner the pulses PEX 1 and PEX 2 supplied to the C/D latch 429 effect that the signal PEG A (FIG. 5) furnished at the output 430 has a high level in each line between the coordinates X1 and X9 and a low level in the remaining portion of the line whilst the complementary signal PEG B furnished at the output 431 has a high level from the coordinate X9 of a line to the coordinate X1 of the following line and a low level between the coordinates X1 and X9.

The misalignment detector 450 illustrated in FIG. 8 includes a line address counter 452 in the form of a three-stage binary counter with two preset inputs to which the signals LNX 1 and LNX 2 respectively are applied by the outputs 414, 415 of the alignment sequencer 400 (FIG. 7). The clock input of the line address counter 452 is connected to the output of a frequency divider 453 to which the line synchronizing pulses LN are supplied and which furnishes at its output pulses having half the recurrence frequency of the line synchronizing pulses LN. The line address counter 452 has an output group 454 having three outputs which are the stage outputs of the three binary counter stages. Thus, at the outputs 454 a group of binary signals appears which express the particular count of the line address counter 452 in the form of a three-digit binary number between 0 and 7. The line address counter 452 is so designed that it is reset to the count 7 by each pulse LNX 1 or LNX 2 supplied to the reset input and then counted down by the pulses supplied to its clock input with half the recurrence frequency of the line synchronizing pulses. For the entire duration of the counting from the start of the presetting until zero count has been reached the line address counter 452 furnishes at a further output 455 a signal LNCT of high level (FIG. 5). This signal LNCT is applied to an enable input of the frequency divider 453 so that the latter emits output pulses only whilst this signal LNCT obtains. Thus, after each presetting by a signal LNX 1 or LNX 2 at the output of the frequency divider 453 a group of eight clock pulses AB-CLK appears with half the recurrence frequency of the line synchronizing pulses LN and the line address counter remains stationary after reaching zero count until the next presetting by a signal LNX 1 or LNX 2. The signal LNCT and the pulse groups AB-CLK emitted for its duration by the output of the frequency divider 453 are also supplied to other points of the circuit as indicated by arrows.

Thus, in the course of each frame the signal LNCT extends from the coordinate Y1 to the coordinate Y2 (LNCT 1) and from the coordinate Y9 to the coordinate Y10 (LNCT 2). The binary numbers appearing during this signal in every other frame line at the outputs 454 denote the numbers of the marker lines A7 to A0 and B7 to B0 which are produced in every other frame line.

In corresponding manner the misalignment detector 450 includes a picture element address counter 456 with two preset inputs which receive the signals PEX 1, PEX 2 from the outputs 417, 418 of the alignment sequencer 400 (FIG. 7) and a clock input which is connected to the output of the frequency divider 466 which receives the picture element pulses PE and furnishes clock pulses with half the recurrence frequency of the picture element pulses PE. The picture element address counter 456 is made up in the same manner as the line address counter 452; it is thus set to the count 7 by each of the pulses PEX 1 and PEX 2 and thereafter counted down until zero count is reached by the clock pulses with half the recurrence frequency of the picture element pulses PE. During this counting it furnishes at a group 458 of three outputs, which are the outputs of the binary counter stages, binary pulse groups which indicate the respective count in the form of a three-digit binary number. At a further output 459 for the entire duration of the counting a signal PECT is furnished which is applied as enable signal to the frequency divider 457 which consequently supplies a group of eight clock pulses CD-CLK after each presetting by a signal PEX 1 or PEX 2. The signal PECT is present in each picture line between the coordinates X1 and X2 (PECT 1) and between the coordinates X9 and X10 (PECT 2). The binary numbers appearing at the outputs 458 indicate the numbers of the marker lines C7 to C0 and D7 to D0 to which the picture elements produced in each frame line by the marker signals MK C and MK D belong.

The three outputs 454 of the line address counter 452 are connected to three associated address inputs of an 8 bit latch 460 which also receives the digital video signals DIGVID A at a signal input, the signal CLR at a clear input and the marker signals MK A (MK A7 to MK A0) at a release input. The 8 bit latch 460 is cleared by the pulse CLR at the start of the frames used for the marking and analysis and thereafter during the frame enabled for the duration of the marker signals MK A for analysis of the digital video signals DIGVID A. It comprises a group of eight outputs which are each associated with one of the eight possible combinations of input signals to the three address inputs and thus with one of the marker lines A7 to A0. If during the scanning of a marker line A whose number is indicated by the binary number at the outputs 454 of the line address counter 452 a white picture element appears the associated output of the 8 bit latch 460 assumes the condition "1" and retains this condition until the 8 bit latch is cleared by a new clear pulse CLR. After termination of all marker signals MK A7 to MK A0 the 8 bit latch 460 has thus reached a state in which a condition "1" exists at those outputs which are associated with the marker lines A and during the course of which at least one white picture element appeared in the signal DIGVID A. The 8 bit latch 460 retains this condition until it is cleared by the next pulse CLR.

The three outputs 454 of the line address counter 452 are further connected to three address inputs of an interrogation circuit 461 which also includes eight data inputs and is so designed that it furnishes at an output 462 the signal which is applied to the data input whose number is represented by the three-digit binary number at the three address inputs. The eight data inputs of the interrogation circuit 461 are connected to the eight outputs of the 8 bit latch 460 in reverse order as indicated in the drawing by crossed arrows, i.e. the output Number 0. of the 8 bit latch is connected to the data input No. 7 of the interrogation circuit, the output No. 1 to the data input No. 6, etc., up to the output No. 7, which is connected to the data input No. 0. The interrogation circuit 461 also has two enable inputs to which the signals LNCT and LNG B respectively are applied so that it operates only during the simultaneous presence of these two signals, i.e. during the signal LNCT 2 in the duration of which formation and analysis of the marker lines B7 to B0 takes place.

Thus, whereas the analysis of the digital video signals DIGVID A takes place in the 8 bit latch 460 under the control of the line addresses which are furnished by the line address counter 452 following the signal LNX 1 and indicate the numbers of the marker lines A7 to A0 during their reproduction, the interrogation of the information stored in the 8 bit latch and available at its outputs is effected in the interrogation circuit 461 under the control of the line addresses which are furnished by the line address counter 452 following the signal LNX 2 and indicate the numbers of the marker lines B7 to B0 during their reproduction. Furthermore, the interrogation is in the reverse order; on reproduction of the first marker line B7, due to the address 7 applied to the address inputs, at the output 462 of the interrogation circuit 461 there appears the signal which is applied to the data input No. 7 and which due to the cross connections is the output signal at the output No. 0 of the 8 bit latch 460, i.e. the signal obtained by the analysis of the digital video signal DIGVID A for the duration of the marker line A0. For the successive addresses 7 to 0 there is thus obtained at the output 462 of the interrogation circuit 461 in succession the information stored in the 8 bit latch for the marker lines A0, A1 . . . A7.

The reason for the analysis of the marker lines A in the reverse order during the formation of the marker lines B is that the marker lines A are produced in the order A7 to A0 (corresponding to the reverse counting of the line address counter 452) but the number of marker lines occupied by white picture elements must be counted from the inside to the outside, i.e. in the order A0, A1 . . . . Since this order is available only after the scanning of all the marker lines A, the evaluation cannot be effected simultaneously with the scanning of the marker lines A but must be done at a later time. For expediency, this evaluation is effected in the course of the formation and evaluation of the marker lines B because the line addresses are then again available at the output of the line address counter 452.

The signals appearing at the output 462 of the interrogation circuit 461 are applied as control signals to an A misalignment counter 463 which receives the marker signals MK B at the clock input and the signal TOP at a release input. The A misalignment counter 463 increases its count by one unit for each marker signal MK B7 to MK B0 if a signal "1" appears at the control input during said marker signal. A suitable input gating circuit terminates the counting when a signal "0" appears for a marker signal MK B at the output 462 of the interrogation circuit 461. After completion of the counting the A misalignment counter 463 has thus assumed a count which corresponds to the number of marker lines counted in uninterrupted succession from the inside to the outside in the course of which at least one white picture element appeared in the digital video signal DIGVID A. The A misalignment counter 463 has a group of five outputs which correspond to the output 451A illustrated in FIG. 1. At three outputs a group of three binary signals AA, AB, AC appears which represent the count reached in the form of a three-digit binary number. At the fourth output an overflow signal AOVR appears whenever the count 7 has been exceeded in the counting of the marker lines because this means that all the eight marker lines of the group A contain white picture elements and consequently correction is not possible on the basis of the data available. At the fifth output a signal COR A appears which indicates that in the region of the marker lines A a state exists which requires a correction. The signal COR A further indicates that the correction must be made in the negative Y-direction (FIG. 4).

Since the formation of the marker lines B7 to B0 takes place in the order in which these marker lines must also be counted, no storage of the information obtained by the analysis in an 8 bit latch and no displaced interrogation by an interrogation circuit is necessary. The digital video signals DIGVID A are therefore applied directly to a B misalignment counter 464 which also receives the marker signals MK B and the signal TOP. The B misalignment counter 464 includes an input gating circuit which effects that the count is increased by one unit for each marker signal MK B7 to MK B0 during which the digital video signal DIGVID A assumes at least once the high signal value (white) but that the counting is terminated when for a marker signal MK B7 . . . MK B0 no high signal value has appeared in the signal DIGVID A, which means that in the portion of the digital video image corresponding to the respective marker line B7 . . . B0 only black picture elements are contained. Thus, after completion of the counting the B misalignment counter 464 has a count which corresponds to the number of marker lines counted in uninterrupted succession from the inside to the outside during which at least one white picture element appeared in the digital video signal DIGVID A. The B misalignment counter 464 has five outputs 451B and furnishes at three outputs a group of three binary numbers BA, BB, BC representing the count, at a fourth output an overflow signal BOVR and at a fifth output a signal COR B which indicates the necessity of a correction and the direction of said correction (positive Y-direction).

The outputs 458 of the picture element address counter 456 are each connected to three address inputs of an 8 bit latch 465 and an interrogation circuit 466. The latch 465 and circuit 466 are constructed and connected in the same manner as the latch 460 and circuit 461. In particular, the outputs of the 8 bit latch 465 are connected in reverse order to the data inputs of the interrogation circuit 466, which is clearly necessary because the marker lines C7 to C0 are generated in an order opposite to the order in which the occupied marker lines must be counted. The 8 bit latch 465 again receives the digital video signal DIGVID A at the signal input and the pulse CLR at the clear input; however, in contrast to the 8 bit latch 460 the marker signals MK C (MK C7 to MK C0) are applied to the release input so that the detection of white picture elements in the signal DIGVID A takes place during the formation of the marker lines C. Corresponding to the formation of these marker lines, the analysis is also not continuous for each marker line; one picture element of each marker line is analysed in successive frame lines. However, as soon as a high signal value (white) is determined in the signal DIGVID A for a picture element of any marker line C in any frame line the output of the 8 bit latch 465 associated with said marker line assumes the condition "1" and retains this condition until the next clear pulse CLR. At the end of the complete reproduction of the marker lines C the outputs of the 8 bit latch 465 associated with marker lines C during which at least one white picture element is present in the digital video image have assumed the condition "1".

The interrogation circuit 466 receives as enable signals the signals PECT and PEG A so that it operates only during the simultaneous existence of these two signals, i.e. during the signal PECT 1 (FIG. 5) in the course of which the marker lines C are generated.

The output 467 of the interrogation circuit 466 is connected to a C misalignment counter 468 which receives the clock pulse groups CD-CLK from the output of the frequency divider 453 at the clock input and the signal TOP at the enable input. A control signal S1 is applied to an additional control input 473 and is formed by a gating (not illustrated) of the signals LN, LNX 2, PEG A, PECT and CD-CLK so that it normally blocks the C misalignment counter 468 and releases the latter only in the frame line corresponding to the signal LNX 2 for the duration of the signal PECT 1. The C misalignment counter 468 thus registers the information appearing at the output 467 of the interrogation circuit 466 only once in the course of a frame, that is after completion of the formation of the complete marker lines C. After this counting the C misalignment counter 468 has a count which indicates the number of marker lines counted in uninterrupted succession from the inside to the outside during which at least one white picture element has been detected. It furnishes at three outputs of its output group 451 C a group of three binary signals CA, CB, CC representing the count, at the fourth output an overflow signal COVR and at the fifth output a signal COR C which indicates the necessity of a correction and the direction of said correction (position X-direction).

The formation of the marker lines D7 to D0, like that of the marker lines B7 to B0, takes place in the sequence in which the occupied marker lines must be counted. Nevertheless, in the case of the marker lines D the analysis results must be retained because the counting is not possible until after complete formation of the marker lines D. Thus, an 8 bit latch 469 and an interrogation circuit 470 are also provided for the marker lines D and the three address inputs of these two circuits are connected, parallel with those of the circuits 465 and 466, to the outputs 458 of the picture element address counter 456. Like the latch 465, the 8 bit latch 469 receives the digital video signals DIGVID A and the clear pulse CLR, but at the enable input receives the marker signals MK D (MK D7 to MK D0) so that the analysis of the signals DIGVID A takes place during the marker lines D. The interrogation circuit 470 is controlled by the enable signals PECT and PEG B so that it operates only during the period of the signal PECT 2. The data inputs of the interrogation circuit 470 are however not connected to the outputs of the 8 bit latch 469 in converse order but in the correct sequence so that the interrogation takes place in the sequence of the marker lines D7, D6 . . . D0. The output 471 of the interrogation circuit 470 is connected to the input of a D misalignment counter 472 which receives the same clock signals CD-CLK and the same enable signal TOP as the C misalignment counter 468. To an additional control input 474 a control signal S2 is applied which is formed by a gating (not illustrated) of the signals LN, LNX 2, PEG B, PECT and CD-CLK so that it normally blocks the D misalignment counter 472 and releases said counter only in the frame line corrresponding to the signal LNX 2 for the duration of the signal PECT 2. The D misalignment counter 472 thus registers the information appearing at the output 471 of the interrogation circuit 470 only once during a frame, and that is after completion of the formation of the complete marker lines D. After this counting the D misalignment counter 472 has a count which indicates the number of the marker lines counted in uninterrupted succession from the inside to the outside during which at least one white picture element has been detected. It comprises a group of five outputs 451D and furnishes at three outputs a group of three binary signals DA, DB, DC representing the count, at the fourth output an overflow signal COVR and at the fifth output a signal COR D which indicates the necessity of a correction and the direction of a correction (negative X-direction).

It should be observed that the 8 bit latch 460 executes only one cycle during each frame whilst the cycle of the 8 bit latch 465, 469 is repeated in each frame line in which marker signals C and D are generated. As soon as a white picture element appears for the first time in the digital video signal DIGVID A in the course of such a cycle during the generation of a certain marker signal MK C or MK D, it is registered by the associated 8 bit latch 465 or 469 and retained until clearance by the next pulse CLR.

In each case the marker signals MK A, MK C, MK D supplied to the 8 bit latches 460, 465, 469 and the marker signal MK B supplied to the misalignment counter 464 form data windows which define the time lengths in which the digital video signal DIGVID A is checked for the presence of white picture elements. These marker signals, whose time variation is shown in FIG. 5, are taken from the corresponding outputs 504, 506, 508, 510 of the marker generator circuits 501, 502 in the marker generator 500 (FIG. 10).

FIG. 9 shows the displacement control device 14. It comprises four groups each with five inputs which are connected to the outputs of the misalignment counters 463, 464, 468, 472 and receive their output signals. The displacement control device 14 determines on the basis of the signals COR A, COR B, COR C, COR D the direction of the correction displacement of the X-Y table 2 to be carried out and on the basis of the numerical values given by one or two of the signal groups AA, AB, AC; BA, BB, BC; CA, CB, CC; DA, DB DC generates the control signals which are applied via the output lines 15, 16 to the X motor 3 and/or Y motor 4 and cause the latter to perform the necessary number of adjustment steps in the correct direction of rotation. Furthermore, the inputs are shown at which the displacement control device 14 receives the output signal DOT of the ink dot detector 650 (FIG. 11), the output signal BAR of the bar detector 750 (FIG. 12) and the output signal EOS of the end of slice detector 800 (FIG. 13). At a further input the signal TOP is supplied to the displacement control device 14 and effects that said device operates only during the frame selected for the marking and analysis in each complete television picture. Furthermore, the setting device 17 for the adjustments JX and JY is shown.

The four signals COR A, COR B, COR C and COR D are also supplied to four inputs of an error detector 480 which performs a digital gating of the form.

ERROR=COR A.COR B+COR C.COR D

and emits a corresponding error signal ERROR at the output. Said error signal thus appears when the markers A and B or the markers C and D simultaneously require a correction, which is obviously not admissible. The error signal ERROR can stop the machine and trigger an alarm for the operator.

When the displacement control device 14 receives an overflow signal AOVR, BOVR, COVR, DOVR it initiates a displacement of the X-Y table 2 by the amount JX (FIG. 2) to bring the next bar into the alignment position. If for a fixed number of successive bars (for example five) an overflow signal occurs the machine is also stopped and an alarm triggered. This step proves expedient because an overflow condition exists frequently only with individual bars; the number of machine stoppages can thereby be substantially reduced.

The marker generator 500 illustrated in FIG. 10 includes an A/B marker generator circuit 501 and a C/D marker generator circuit 502. The A/B marker generator 501 receives at five inputs the following signals:

AB-CLK (from the output of the frequency divider 453, FIG. 8)

CD-CLK (from the output of the frequency divider 457, FIG. 8)

PEG A (from the output 430 of the C/D latch 429, FIG. 7)

PECT (from the output 450 of the picture element address counter 456, FIG. 8)

LNCT (from the output 455 of the line address counter 452, FIG. 8).

From these signals, by digital gatings signals are formed which in every other frame line of the frame portions defined by the signal LNCT have the high signal value (white) between the coordinates X2 (end of PECT 1) and X9 (end of PEG A). If the signal LNG A applied to a first control input 503 has the high signal value the signals obtained by the gating are emitted only at a first output 504; thus, the marker signals MK A are obtained at this output.

If signal LNG B applied to a second control input 505 has the high signal value the signals obtained by the gating are emitted only at a second output 506; the marker signals MK B are thus obtained at this output.

The C/D marker generator circuit 502 receives at five inputs the following signals:

CD-CLK (from the output of the frequency divider 457, FIG. 8)

AB-CLK (from the output of the frequency divider 453, FIG. 8)

LNG A (from the output 427 of the A/B latch 426, FIG. 7)

LNCT (from the output 455 of the line address counter 452, FIG.8)

PECT (from the output 459 of the picture element address counter 456, FIG. 8)

By digital gating from these signals signals are obtained which on each clock pulse of the clock pulse groups CD-CLK have the high signal value (white) in each frame line of the frame portion lying between the coordinates Y2 (end of LNCT 1) and Y9 (end of LNG A). If the signal PEG A applied to a first control input 507 has the high signal value the signals obtained by the gating are emitted only at the first output 508; the marker signals MK C are thus obtained at said output. If the signal PEG B applied to a second control input 509 has the high signal value the signals obtained by the gating are emitted at a second output 510; the marker signals MK D are thus obtained at this output.

The outputs 504, 506, 508, 510 of the two marker generator circuits 501, 502 are connected to four inputs of an OR gate 511 which receives at a fifth input the marker signal MK E (from the output of the ink dot sequencer 600 (FIG. 11)).

Thus, at the output of the OR circuit 511 a composite marker signal MK A-E is obtained which can be supplied via the video selector and mixer 100 to the monitor 10 for displaying the marker lines A, B, C, D and the marker field E.

FIG. 11 shows the circuits for the ink dot recognition, consisting of the ink dot sequencer 600 and the ink dot detector 650.

The ink dot sequencer 600 includes a memory 603 having a capacity of four words×8 bits. With the aid of the control means 602 connected to the input 601 data can be fed into the memory 603 in accordance with the location and size of the ink dot 56 on the bars 52 to be processed (FIG. 2), said data defining the borders Y5, Y6, X5, X6 of the marker field E by the numbers of the lines to be counted in the frame and picture elements to be counted in each line. The memory 603 has an output 604, an address input 605 and an enable input 606.

The output 604 is connected to the preset inputs of a line counter 607 and a picture element counter 608. The line counter 607 receives at its clock input the line synchronizing pulses LN and the picture element counter 608 receives at its clock input the picture element pulses PE. The address input 605 and enable input 606 of the memory 603 are connected to two outputs of a memory address and strobe decode 609 which receives at two trigger inputs the signals LNCT and PECT and at two enable inputs the signals LNG A and PEG A. Two further trigger inputs of the memory address and strobe decode 609 are connected to the output 610 of the line counter 607 and the output 611 of the picture element counter 608, and two further outputs of the memory address and strobe decode 609 are connected to the preset control inputs of the two counters 607, 608.

The circuits 603, 607, 608, 609 described are identical to the circuits 403, 407, 408 and 419 of FIG. 7 and are connected together in a manner very similar to the latter. The mode of operation is also substantially the same. The only differences are as follows: The first input of a memory word into the line counter 607 is initiated in each frame by the signal LNCT during the existence of the signal LNG A and said memory word indicates the number of the frame lines to be counted from the trailing edge of the signal LNCT up to the coordinate Y5. the line counter 607 counts down from this preset number and on reaching zero count emits a pulse EMLN 1 at the output 610. This pulse thus indicates the frame line corresponding to the coordinate Y5 in which the upper limit of the marker field E lies. The same pulse is supplied to a trigger input of the memory address and strobe decode 609 and initiates the transfer of the second memory word to the line counter 607, which indicates the number of frame lines to be counted between the coordinates Y5 and Y6. The line counter 607 counts down from this new presetting and on reaching zero count furnishes at the output 610 a further pulse EMLN 2 which indicates the frame line with the coordinate Y6 in which the lower border of the marker field E lies.

In corresponding manner, in each frame line the introduction of the third memory word into the picture element counter 608 is initiated by the signal PECT during the existence of the signal PEG A, said memory word indicating the number of picture elements to be counted from the end of the signal PECT up to the coordinate X5. On reaching zero count the picture element counter 608 furnishes at the output 611 a pulse EMPE 1 which coincides with the coordinate X5 and thus corresponds to the left border of the marker field E. This pulse initiates the introduction of the fourth memory word into the picture element counter 608 which indicates the number of picture elements to be counted between the coordinates X5 and X6. On reaching zero count the picture element counter 608 furnishes a further pulse EMPE 2 which thus corresponds to the right border of the marker field E. This operation is repeated in each frame line during the existence of the signal LNG A.

It should be noted that the operations described take place in every frame, i.e. not only in every other frame selected by the signal TOP.

The feature described of counting the line and picture elements from the signals LNCT and PECT onwards respectively instead of from the frame beginning and line beginning has the advantage that the words to be recorded in the memory can be fixed once and for all for each bar type, irrespective of the locations of the markers on the television picture.

It is therefore possible to displace the markers on the television picture as desired without having to change the memory words for the marker field E.

The outputs 610 and 611 of the line counter 607 and the picture element counter 608 respectively are connected to the two inputs 613, 614 of an E marker generator 612. The latter is so designed that it is brought into the operative position by each pulse EMLN 1 supplied to the input 613 and returned to the inoperative position by each pulse EMLN 2. In the operative position each pulse EMPE 1 applied to the input 614 brings the output signal at the output 615 to the high signal level (white) which is also retained even after the end of the pulse EMPE 1, and each pulse EMPE 2 resets the output signal to the low signal level again. It is immediately apparent from FIG. 5 that the signals obtained in this manner at the output 615 are the marker signals MK E. These are supplied on the one hand to the input of the ink dot detector 650 and on the other to the OR circuit 511 in the marker generator 500 (FIG. 10).

The ink dot detector 650 includes an ink dot control 652 which receives at an input 653 the marker signals MK E, at a further input 654 the digital video signals DIGVID B and at a third input 655 the picture element pulses PE. The ink dot control 652 performs an AND-gating of the three input signals, the digital video signal DIGVID B being inverted at the input 654. It thus emits at its output 656 an output signal for each pulse PE supplied in the course of the marker signals MK E if simultaneously the digital video signal DIGVID B has the low signal level (black). The output pulses of the ink dot control 652 thus correspond to the black picture elements, contained in the marker field E, of the digital video image represented by means of the signal DIGVID B.

The output 656 of the ink dot control 652 is connected to the input of a pulse frequency divider 657 whose division factor is adjustable by means of a setting device 658 to different values, for example to the values 1:1,5:1,10:1,50:1. Connected to the output of the pulse frequency divider 657 is a counter 659 which thus counts the number of the black picture elements of the signal DIGVID B present in the marker field E divided by the set division factor of the pulse frequency divider 657.

The stage outputs of the counter 659 are connected to one input group of a comparator 660, at the other input group of which any desired binary number can be set with the aid of the setting device 651. As soon as the comparator 660 detects identity of the count reached in the counter 659 and the set number it furnishes at the output 661 a signal which brings the ink dot latch 662 into the operative position until it is returned to the inoperative state by the next pulse CLR, and said latch furnishes in the operative state at its output the signal DOT which indicates the presence of an ink dot on the analysed bar. The counter 659 is enabled by the signal TOP and on completion thereof reset to zero.

The sensitivity of the ink dot detector can be set by adjusting the division factor of the pulse frequency divider 657 by means of the setting device 658. The threshold number is set by means of the setting device 651 in adaptation to the magnitude fluctuations of the ink dot to be expected so that the number of black picture elements counted is with certainty above the threshold number even for the smallest ink dot which occurs.

FIG. 12 shows the bar recognition circuit comprising the bar sequencer 700 and the bar detector 750. The latter contains two circuit groups which have the same makeup and mode of operation as the circuit group consisting of the circuit 603, 607, 608 and 609 of FIG. 11. The first circuit group consists of the memory 703, the line start counter 704, the picture element start counter 705 and the memory address and strobe decode 706. The second circuit group consists of the memory 713, the line stop counter 714, the picture element stop counter 715 and the memory address and storbe circuit 716. The only difference in the mode of operation results from the meaning of the words which are fed into the memories 703 and 713 at the input 701 with the aid of the control means 702:

The first memory word of the memory 703, which is introduced into the line start counter 704 in each frame under the control of the signals LNG A and LNCT for presetting, causes on reaching zero count a pulse FMLN 1A to be emitted at the output 707 of the counter 704; this pulse (FIG. 5) defines the coordinate Y3 of the upper border of the marker fields F1 and F2.

The second memory word of the memory 703, which is introduced into the line start counter 704 in each frame under the control of the pulse FMLN 1A for presetting, causes on reaching zero count a pulse FMLN 1B to be emitted at the output 707; this pulse (FIG. 5) defines the coordinate Y7 of the upper border of the marker fields F3 and F4.

The third memory word of the memory 703, which is introduced into the picture element start counter 707 in each frame line under the control of the signals PEG A and PECT for presetting, causes on reaching zero count a pulse FMPE 1A to be emitted at the output 708 of the counter 705; this pulse defines the coordinate X3 of the left border of the marker fields F1 and F3.

The fourth memory word of the memory 703, which is introduced into the picture element start counter 705 in each frame line under the control of the signal FMPE 1A for presetting, causes on reaching zero count a pulse FMPE 1B to be emitted at the output 708; this pulse defines the coordinate X7 of the border of the marker fields F2 and F4.

The first memory word of the memory 713, which is introduced into the line stop counter 714 in each frame under the control of the signals LNG A and LNCT for presetting, causes on reaching zero count a pulse FMLN 2A to be emitted at the output 717 of the counter 714; this pulse defines the coordinate Y4 of the lower border of the marker fields F1 and F2.

The second memory word of the memory 713, which is introduced into the line stop counter 714 in each frame under the control of the pulse FMLN 2A for presetting, causes on reaching zero count a pulse FMLN 2B to be emitted at the output 717; this pulse defines the coordinate Y8 of the lower border of the marker fields F3 and F4.

The third memory word of the memory 713, which is introduced into the picture element stop counter 715 in each frame line under the control of the signals PEG A and PECT for presetting, causes on reaching zero count a pulse FMPE 2A to be emitted at the output 718 of the counter 715; this pulse defines the coordinate X4 of the right border of the marker fields F1 and F3.

The fourth memory word of the memory 713, which is introduced into the picture element stop counter 715 in each frame line under the control of the pulse FMPE 2A for presetting, causes on reaching zero count a pulse FMPE 2B to be emitted at the output 718; this pulse defines the coordinate X8 of the right border of the marker fields F2 and F4.

The outputs 707, 708, 717, 718 of the four counters 704, 705, 714, 715 are connected to inputs of an F marker generator 720 which also receives at further inputs the signals LNG A, LNCT, LN, PEG A, PECT, PE which are required as control signals in the formation of the marker signals MK F. The mode of operation of the F marker generator 720 may be described in simplified manner as follows: The F marker generator is brought into an operative condition by each pulse FMLN 1 (FMLN 1A or FMLN 1B) and returned to the inoperative position by each pulse FMLN 2 (FMLN 2A or FMLN 2B). In the inoperative position the output signal at the output 721 is always at the lower signal level (black). In the operative condition each pulse FMPE 1 (FMPE 1A or FMPE 1B) brings the output signal to the high signal level which it also retains when the pulse FMPE 1 ceases, and each pulse FMPE 2 (FMPE 2A or FMPE 2B) returns the output signal to the low signal level. It is immediately apparent that the signals obtained in this manner at the output 721 of the F marker generator 720 represent the desired marker signals MK F. These signals are supplied on the one hand to the video selector and mixer 100 (FIG. 6) for displaying the marker fields F1 to F4 on the screen and on the other hand are applied to the input of the bar detector 750.

The bar detector 750 includes a bar control 752 which receives at one input the marker signals MK F and at another input the digital video signal DIGVID A. The picture element pulses PE and the signal TOP are applied to further inputs of the bar control 752. The bar control 752 conducts an AND gating of its input signals; consequently, it furnishes in each frame selected by the signal TOP during the existence of a marker signal MK F for each picture element pulse PE an output pulse if simultaneously the digital video signal DIGVID A has a high signal level (white). The pulses furnished by the bar control 752 thus correspond to the number of white picture elements which are present in the corner regions covered by the marker fields F1 to F4 of the digital video image displayed by means of the signal DIGVID A.

The output pulses of the bar control 752 are fed to a pulse counter 753 which is enabled by the signal TOP in the frames selected for the marking and analysis and reset to zero at the end of said signal. The pulse counter 753 has a plurality of outputs at which it furnishes a pulse on reaching certain counts. For example, one output may correspond to the count 50, a further output to the count 250 and a third output to the count 2500. By means of the setting device 751 one of these outputs can be connected selectively to the input of a bar latch 754 which is brought into the operative condition by the output pulse of the pulse counter 753 and retains this condition until it is reset to the inoperative position by the next pulse CLR. In the operative position the bar latch 754 furnishes a signal BAR at its output. The signal BAR thus indicates that the total number of white picture elements in the corner areas of the digital video image corresponding to the four marker fields F1 to F4 has exceeded the threshold number set by means of the setting device 751; this fact is considered a criterion for the presence of a complete bar. If the signal BAR is missing after complete analysis of the frame this means that the bar is damaged or missing. As previously explained in this case the displacement control device 14 effects a search for a new bar by indexing in the X or Y direction.

FIG. 13 shows the end of slice detector 800. The latter contains an end of slice control 802 which receives at one input the digital video signals DIGVID A, at a second input the pulses PE and at a third inverting input the line synchronizing pulses LN. It conducts an AND gating of its input signals so that for each pulse PE it furnishes a pulse at the output if simultaneously the digital video signal DIGVID A has the high signal level (white). The output pulses of the end of slice control 802 thus correspond to the total number of white picture elements which are present in the entire digital video image displayed by means of the signal DIGVID A. These pulses are counted in a pulse counter 803 which has a plurality of outputs at which it furnishes a pulse on reaching certain counts; for example, one output may correspond to the count 2500 and a further output to the count 125,500. The pulse counter 803 is enabled by the signal TOP in the frames intended for the marking and analysis and reset to zero on completion of said signal. By means of the setting device 801 one of its outputs can be connected selectively to the input of an end of slice latch 804 which is brought into the operative position by the pulse emitted when the selected count is exceeded and retains said position until it is reset to the inoperative position by the next pulse CLR. In the inoperative position the end of slice latch furnishes at a negated output a signal EOS which disappears when the latch goes over to the operative condition. The presence of the signal EOS at the end of the complete scanning of the frame thus means that the number of white picture elements set is not present in the entire frame; this fact is taken as a criterion indicating that all the rows of bars on the carrier 50 have been run through and only the empty base 54 is now being scanned. On the basis of the signal EOS the displacement control device 14 stops the machine and alarms the operator so that he can replace the used carrier 50 by a new one.

FIG. 14 shows a more exact circuit diagram of the video digitizer 200 and indicates how a signal obtained by peak detecting of the video signal is used to adjust the threshold voltages so that the digital video signals DIGVID A and DIGVID B are substantially independent of intensity fluctuations of the video image from which they are generated.

FIG. 15 shows a more exact circuit of the line counter 407 of FIG. 7. The picture element counter 408 is similarly constructed except that the input signals LN and FR of FIG. 15 are replaced by the input signals PE and LN respectively, and that instead of the output signals LNX 1 and LNX 2 of FIG. 15 the output signals PEX 1 and PEX 2 respectively are emitted.

FIG. 16 shows various parts of the block circuit diagrams of FIGS. 7, 8 and 10. From the alignment sequencer 400 of FIG. 7 the A/B latch 426 is shown which is formed by a flip-flop of the type SN 7474 which furnishes at its two complementary outputs Q and Q the signals LNG A and LNG B respectively. The C/D latch 429 is constructed in the same manner with a flip-flop of the type SN 74S74 and furnishes the signals PEG A and PEG B.

The line address counter 452 includes a synchronous-bit up-down counter of the type SN 74193 which furnishes at its three outputs A, B, C the three address bits and at a fourth output BW the signal LNCT. The frequency divider 453 is a flip-flop of the type SN 7474 whose clock input CLK (terminal 3) receives the line synchronizing pulses LN and whose clear input C receives the signal LNCT inverted. In corresponding manner the picture element address counter 456 includes a 4 bit up-down counter of the type SN 74193 which furnishes at three outputs A, B, C the three address bits and at a fourth output BW the signal PECT. The frequency divider 457 is a flip-flop of the type SN 74S74 which receives at its clock input CLK the picture element pulses PE and to the clear input of which the signal PECT is applied inverted.

FIG. 16 further shows the marker generator circuit 501 and 502. The A/B marker generator circuit 501 contains two flip-flops of the type SN 7474 and two NAND circuits of the type SN 7420; the one NAND circuit receives at one input the signal LNG A and furnishes at the output (after inversion) the marker signals MK A and the other NAND circuit receives at an input the signal LNG B and furnishes at the output (after inversion) the marker signals MK B. The C/D marker generator circuit 502 likewise contains two flip-flops of the type SN 74S74 and two NAND circuits of the type SN 74S20; the one NAND circuit receives at an input the signal PEG A and furnishes at the output (after inversion) the marker signals MK C and the other NAND circuit receives at an input the signal PEG B and furnishes at the output (after inversion) the marker signals MK D.

Furthermore, FIG. 16 shows the OR circuit 511 of the type SN 4931 which receives the marker signals MK A, MK B, MK C, MK D, MK E and forms therefrom the composite marker signal MK A-E.

The FIGS. 17A and 17B show further components of the misalignment detector 450 of FIG. 8. The 8 bit latch 460 is formed by a circuit of the type Am 93L34 (=SN 74259) in conjunction with an "8 to 1" multiplexer of the type SN 74151 effecting the latching; a second "8 to 1" multiplexer of the type SN 74151 forms the interrogation circuit 461. The A misalignment counter 463 contains a 4 bit counter of the type SN 74193 and the associated input gating circuit. The B misalignment counter 464 includes also a 4 bit counter of the type SN 74193 and the associated input gating circuit; it also receives directly the digital video signals DIGVID A. The 8 bit latch 465 is again formed by a circuit of the type Am 93L34 (=SN 74259) in conjunction with an "8 to 1" multiplexer SN 74S151; a second "8 to 1" multiplexer SN 74S151 forms the interrogation circuit 466. The C misalignment counter 468 includes a 4 bit counter SN 74193 and the associated input gating circuit which receives the signal S1 at an additional input 473. The 8 bit latch 469 is also formed by a circuit of the type Am 93L34 (=SN 74259) in conjunction with an "8 to 1" multiplexer 74S151 which serves in this case at the same time as interrogation circuit 470, which is possible because the sequence of the connections between the 8 bit latch and the interrogation circuit is not inverted. The D misalignment counter 472 includes a 4 bit counter SN 74193 and the associated input gating circuit which receives at an additional input 474 the signal S2. The four misalignment counters of the type SN 74193 each furnish at the three outputs A, B, C the signal combination indicating the count and at the output BW the signal COR A, COR B, COR C, and COR D respectively.

FIGS. 18 and 19 show some parts of the ink dot sequencer 600 of FIG. 11 in greater detail. As apparent from FIG. 18, the memory address and strobe decode 609 and the E marker generator 612 include flip-flops of the type 74LS74 and associated gating circuits; the marker signals MK E are obtained at the output of a NAND circuit of the type SN 4931 (after inversion). FIG. 19 shows the line counter 607 and the picture element counter 608. Each of these counters is formed by a pair of 4 bit counters of the type SN 74LS193, the output BW of the one counter being connected to the clockdown input of the other counter whose output BW then forms the output 610 and 611 (FIG. 11) respectively which provides the pulses EMLN or EMPE in the manner illustrated in FIG. 5. Furthermore, in FIG. 19 the memory 603 is shown and is formed by a pair of memory registers of the type 74LS670.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3515877 *Dec 13, 1965Jun 2, 1970Claude B SmoyerElectro-optical positioner
US3562423 *Aug 15, 1967Feb 9, 1971Univ NorthwesternDictorial tracking and recognition system which provides display of target identified by brilliance and spatial characteristics
US3814845 *Mar 1, 1973Jun 4, 1974Bell Telephone Labor IncObject positioning
US3816651 *Sep 22, 1972Jun 11, 1974Image Analysing Computers LtdAutomated image analysis employing automatic focussing
US3870814 *Sep 11, 1973Mar 11, 1975Mosler Safe CoImage positioning apparatus and method
US3899634 *Jul 11, 1973Aug 12, 1975Western Electric CoVideo controlled positioning method and apparatus
US3903363 *May 31, 1974Sep 2, 1975Western Electric CoAutomatic positioning system and method
US3936800 *Mar 27, 1974Feb 3, 1976Hitachi, Ltd.Pattern recognition system
US3958740 *Jul 8, 1974May 25, 1976Dixon Automation, Inc.Automatic component assembly machine and method relating thereto
US3988535 *Nov 4, 1975Oct 26, 1976Western Electric Company, Inc.Automated positioning
DE2722567A1 *May 18, 1977Nov 24, 1977Hitachi LtdLageerkennungssystem
FR2219398A1 * Title not available
Non-Patent Citations
Reference
1 *"Wire-Bonding Speed Increased" Electronics, Jan. 19, 1978, pp. 148, 150.
2 *Automatic CCTV Positioning System, Duffy et al., IBM Tech. Disc. Bul., vol. 14, No. 8, Jan. 1972, pp. 2348-2350.
3 *Automatic High Speed Wire Bonders, Model WB 1411/1421/1431, Rikei Corp. of America.
4 *Automatic Optical Micrometer-Model RB-1, View Engineering Inc.
5 *Die Bonder, Helmut Seier AG.
6 *Kulicke & Soffa, Operatorless Wire Bonding System, Model 1414-1415.
7 *Tacmatic Die Handling Systems, Teledyne, TAC.
8 *Video Measuring System, IBM Tech. Disc. Bull., vol. 11, No. 3, Aug. 1968, pp. 287-288.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4479145 *Jul 22, 1982Oct 23, 1984Nippon Kogaku K.K.Apparatus for detecting the defect of pattern
US4496970 *Aug 14, 1981Jan 29, 1985Jenoptik Jena G.M.B.H.Arrangement for the automatic adjustment of at least one object
US4651203 *Oct 29, 1985Mar 17, 1987At&T Technologies, Inc.Video controlled article positioning system
US4672676 *Dec 20, 1984Jun 9, 1987International Business Machines Corp.Method and apparatus for automatically aligning an object with respect to a reference pattern
US4731745 *Dec 3, 1984Mar 15, 1988Shin-Etsu Engineering Co., Ltd.Automatic dimension analyzer
US4896206 *Feb 21, 1989Jan 23, 1990Electro Science Industries, Inc.Video detection system
US4949390 *Jul 11, 1989Aug 14, 1990Applied Vision Systems, Inc.Interconnect verification using serial neighborhood processors
US5097602 *Jul 9, 1990Mar 24, 1992Westinghouse Electric Corp.Apparatus and method for automated inspection of a surface contour on a workpiece
US6320624Jan 16, 1998Nov 20, 2001ECOLE POLYTECHNIQUE FéDéRALEMethod and system for combining video sequences with spatio-temporal alignment
US6481614 *Mar 15, 2001Nov 19, 2002Esec Trading SaApparatus for mounting semiconductor chips on a substrate
US7112812Dec 28, 2001Sep 26, 2006Applied Materials, Inc.Optical measurement apparatus
US7843510Jan 19, 1999Nov 30, 2010Ecole Polytechnique Federale De LausanneMethod and system for combining video sequences with spatio-temporal alignment
US8285791Oct 23, 2009Oct 9, 2012Wireless Recognition Technologies LlcMethod and apparatus for sharing information using a handheld device
US8675021Sep 9, 2009Mar 18, 2014Dartfish SaCoordination and combination of video sequences with spatial and temporal normalization
EP0142357A2 *Nov 9, 1984May 22, 1985Shin-Etsu Engineering Co Ltd.Automatic dimension analyzer
WO1984002024A1 *May 9, 1983May 24, 1984Tre CorpHigh speed alignment method for wafer stepper
Classifications
U.S. Classification348/87, 257/E23.179
International ClassificationG06T7/00, H01L21/68, G06T1/00, H01L23/544
Cooperative ClassificationG06T2207/30148, G06K2009/3225, H01L21/681, G06T7/0042, G06K9/3216, H01L23/544, G06T2207/30204
European ClassificationG06T7/00P1, H01L23/544, H01L21/68L, G06K9/32P